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<!-- Creation Date :2026-03-11T16:24:58.7321+00:00 -->
<!-- Copyright (c) 2026 Donnelley Financial Solutions, Inc. All Rights Reserved. -->
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          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Class of Financing Receivable [Axis]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Class of Financing Receivable</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_USGovernmentAgenciesDebtSecuritiesMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">US Government Agencies Debt Securities [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_USGovernmentAgenciesDebtSecuritiesMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">US Government Agencies Debt Securities [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AllowanceForLoanAndLeaseLossRecoveryOfBadDebts_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Allowance for Loan and Lease Loss, Recovery of Bad Debts</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AllowanceForLoanAndLeaseLossRecoveryOfBadDebts_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Recoveries</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FairValueInputsLevel2Member_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Fair Value, Inputs, Level 2 [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FairValueInputsLevel2Member_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Fair Value, Inputs, Level 2 [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_InterestRateFloorContractsTwoMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Interest Rate Floor Contracts Two [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_InterestRateFloorContractsTwoMember_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Interest rate floor contracts two.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_InterestRateFloorContractsTwoMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Interest Rate Floor Contracts Two [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_CommitmentsAndContingenciesDisclosureTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Commitments and Contingencies Disclosure [Text Block]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_CommitmentsAndContingenciesDisclosureTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Guarantees, Commitments and Contingencies</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_CashFlowHedgingMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Cash Flow Hedging [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_CashFlowHedgingMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Cash Flow Hedging [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_CommonStockSharesAuthorized_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Common Stock, Shares Authorized</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_CommonStockSharesAuthorized_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Common stock, shares authorized (in shares)</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_OtherNonInterestExpenseMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Other Non-Interest Expense [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_OtherNonInterestExpenseMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Other Non-Interest Expense [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_OtherNonInterestExpenseMember_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Other non-interest expense.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodTax_lbl" xlink:role="http://www.xbrl.org/2003/role/label">OCI, Debt Securities, Available-for-Sale, Unrealized Holding Gain (Loss), before Adjustment, Tax</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodTax_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Unrealized holding gains on securities available-for-sale arising during the year, tax expense</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_ScheduleOfOtherOperatingIncomeByComponentTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Schedule of other operating income by component.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_ScheduleOfOtherOperatingIncomeByComponentTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Schedule Of Other Operating Income By Component [Text Block]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_ScheduleOfOtherOperatingIncomeByComponentTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Other Operating Income</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="srt_ProductOrServiceAxis_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Product and Service [Axis]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="srt_ProductOrServiceAxis_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Product and Service</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LoansInsuredOrGuaranteedByGovernmentAuthoritiesAxis_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Loans Insured or Guaranteed by Government Authorities [Axis]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LoansInsuredOrGuaranteedByGovernmentAuthoritiesAxis_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Loans Insured or Guaranteed by Government Authorities</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationByLiabilityClassDomain_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Fair Value by Liability Class [Domain]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="dei_DocumentFiscalPeriodFocus_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Document Fiscal Period Focus</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="dei_DocumentFiscalPeriodFocus_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Document Fiscal Period Focus</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_OperatingLeaseRightOfUseAssetStatementOfFinancialPositionExtensibleList_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Operating Lease, Right-of-Use Asset, Statement of Financial Position [Extensible Enumeration]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_IndirectMember_lbl" xlink:role="http://www.xbrl.org/2003/role/verboseLabel">Indirect Consumer [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_IndirectMember_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Indirect.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_IndirectMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Indirect [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_IndirectMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Indirect [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DebtInstrumentInterestRateStatedPercentage_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Debt Instrument, Interest Rate, Stated Percentage</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DebtInstrumentInterestRateStatedPercentage_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Loan, fixed interest rate</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="dei_EntityShellCompany_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Entity Shell Company</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="dei_EntityShellCompany_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Entity Shell Company</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ServiceMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Service [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ServiceMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Service [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_SegmentReportingPolicyPolicyTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Segment Reporting, Policy [Policy Text Block]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_SegmentReportingPolicyPolicyTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Segment Reporting</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_CashAndCashEquivalentsAtCarryingValue_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Cash and Cash Equivalent</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_CashAndCashEquivalentsAtCarryingValue_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Cash on deposit</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_CashAndCashEquivalentsAtCarryingValue_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Total cash and cash equivalents</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ScheduleOfMaturitiesOfLongTermDebtTableTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Schedule of Maturities of Long-Term Debt [Table Text Block]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ScheduleOfMaturitiesOfLongTermDebtTableTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Summary of Long-Term Borrowings</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="cyd_CybersecurityRiskManagementStrategyAndGovernanceAbstract_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Cybersecurity Risk Management, Strategy, and Governance [Abstract]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_CommonStockSharesIssued_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Common Stock, Shares, Issued</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_CommonStockSharesIssued_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Common stock, shares issued (in shares)</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="cyd_CybersecurityRiskManagementPositionsOrCommitteesResponsibleReportToBoardFlag_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Cybersecurity Risk Management Positions or Committees Responsible Report to Board [Flag]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="cyd_CybersecurityRiskBoardOfDirectorsOversightTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Cybersecurity Risk Board of Directors Oversight [Text Block]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ScheduleOfShortTermDebtTable_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Short-Term Debt [Table]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ScheduleOfShortTermDebtTable_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Schedule Of Short Term Debt [Table]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_StatementTable_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Statement [Table]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_StatementTable_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Statement [Table]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_ForwardInterestRateSwapContractsThreeMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Forward Interest Rate Swap Contracts Three [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_ForwardInterestRateSwapContractsThreeMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Forward Interest Rate Swap Contracts Three [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_ForwardInterestRateSwapContractsThreeMember_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Forward interest rate swap contracts three.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_TierOneRiskBasedCapitalRequiredForCapitalAdequacyToRiskWeightedAssets_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Banking Regulation, Tier 1 Risk-Based Capital Ratio, Capital Adequacy, Minimum</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_TierOneRiskBasedCapitalRequiredForCapitalAdequacyToRiskWeightedAssets_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Tier 1 capital (to risk-weighted assets), Minimum Requirement</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_InterestReceivable_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Interest Receivable</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_InterestReceivable_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Accrued interest receivable</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_NoninterestBearingDepositLiabilities_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Noninterest-Bearing Deposit Liabilities</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_NoninterestBearingDepositLiabilities_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Non-interest-bearing</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_NoninterestBearingDepositLiabilities_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Noninterest-Bearing Deposit Liabilities, Total</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_HeldToMaturitySecuritiesContinuousUnrealizedLossPositionTwelveMonthsOrLongerFairValue_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Debt Securities, Held-to-Maturity, Continuous Unrealized Loss Position, 12 Months or Longer, Fair Value</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_HeldToMaturitySecuritiesContinuousUnrealizedLossPositionTwelveMonthsOrLongerFairValue_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Held-to-maturity, 12 months or more, fair value</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LoansAndLeasesReceivableRelatedPartiesAdditions_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Loans and Leases Receivable, Related Parties, Additions</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LoansAndLeasesReceivableRelatedPartiesAdditions_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Loans and Leases Receivable, Related Parties, Additions</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_FederalFundsSoldAndSecuritiesPurchasedUnderReverseRepurchaseAgreementsFairValueDisclosure_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Federal funds sold and securities purchased under reverse repurchase agreements</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_FederalFundsSoldAndSecuritiesPurchasedUnderReverseRepurchaseAgreementsFairValueDisclosure_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Federal Funds Sold and Securities Purchased under Reverse Repurchase Agreements Fair Value Disclosure</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_FederalFundsSoldAndSecuritiesPurchasedUnderReverseRepurchaseAgreementsFairValueDisclosure_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Federal funds sold and securities purchased under reverse repurchase agreements fair value disclosure.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LoansAndLeasesReceivableRelatedPartiesProceeds_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Loans and Leases Receivable, Related Parties, Proceeds</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LoansAndLeasesReceivableRelatedPartiesProceeds_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Loans and Leases Receivable, Related Parties, Proceeds</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FinancingReceivableOriginatedFourYearsBeforeLatestFiscalYear_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Financing Receivable, Year Five, Originated, Four Years before Current Fiscal Year</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FinancingReceivableOriginatedFourYearsBeforeLatestFiscalYear_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">2021</link:label>
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          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_HeldToMaturitySecuritiesDebtMaturitiesAfterOneThroughFiveYearsNetCarryingAmount_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Held-to-maturity, maturing after one to five years, amortized cost</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_StockRepurchaseProgramRemainingNumberOfSharesAuthorizedToBeRepurchased_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Share Repurchase Program, Remaining Authorized, Number of Shares</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_StockRepurchaseProgramRemainingNumberOfSharesAuthorizedToBeRepurchased_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Number of shares remained available for repurchase</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_FederalFundsSoldFairValueDisclosure_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Fair value portion of federal funds sold.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_FederalFundsSoldFairValueDisclosure_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Federal Funds Sold Fair Value Disclosure</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_FederalFundsSoldFairValueDisclosure_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Federal funds sold</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_StatementLineItems_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Statement [Line Items]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_StatementLineItems_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Statement [Line Items]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_TreasuryStockValueAcquiredCostMethod_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Treasury Stock, Value, Acquired, Cost Method</link:label>
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          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_BusinessAcquisitionAcquireeDomain_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Business Combination [Domain]</link:label>
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          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsExpirationsInPeriodWeightedAverageExercisePrice_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Expired, weighted-average exercise price (in dollars per share)</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_TierOneRiskBasedCapital_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Banking Regulation, Tier 1 Risk-Based Capital, Actual</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_TierOneRiskBasedCapital_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Tier 1 capital (to risk-weighted assets) Actual Regulatory Capital, Amount</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="dei_EntityFilerCategory_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Entity Filer Category</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="dei_EntityFilerCategory_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Entity Filer Category</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_PriorPeriodReclassificationAdjustmentDescription_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Reclassification, Comparability Adjustment [Policy Text Block]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_PriorPeriodReclassificationAdjustmentDescription_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Reclassification</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FinancingReceivables60To89DaysPastDueMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Financial Asset, 60 to 89 Days Past Due [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FinancingReceivables60To89DaysPastDueMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Financial Asset, 60 to 89 Days Past Due</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_MaximumMaturityPeriodForCashEquivalents_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Represents the maximum maturity period for cash equivalents.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_MaximumMaturityPeriodForCashEquivalents_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Maximum Maturity Period For Cash Equivalents</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_MaximumMaturityPeriodForCashEquivalents_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Maximum maturity period for cash equivalents</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ScheduleOfFinancingReceivablesPastDueTable_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Financing Receivable, Past Due [Table]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LiabilitiesAndStockholdersEquity_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Liabilities and Equity</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LiabilitiesAndStockholdersEquity_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Total liabilities and shareholders&#8217; equity</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DebtInstrumentLineItems_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Debt Instrument [Line Items]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DebtInstrumentLineItems_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Debt Instrument [Line Items]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ResidentialMortgageBackedSecuritiesMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Residential Mortgage-Backed Securities [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ResidentialMortgageBackedSecuritiesMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Residential Mortgage Backed Securities [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_NoninterestIncome_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Noninterest Income</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_NoninterestIncome_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Total non-interest income</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_NoninterestIncome_lbl" xlink:role="http://www.xbrl.org/2003/role/verboseLabel">Income</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_NoninterestIncome_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Non-interest income</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableWeightedAverageExercisePrice_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Exercisable, Weighted Average Exercise Price</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableWeightedAverageExercisePrice_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Options exercisable, end of year, weighted average exercise price (in dollars per share)</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_RestructuringCostAndReserveAxis_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Restructuring Type [Axis]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_RestructuringCostAndReserveAxis_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Restructuring Type</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_PropertyPlantAndEquipmentByTypeAxis_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Long-Lived Tangible Asset [Axis]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_PropertyPlantAndEquipmentByTypeAxis_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Long-Lived Tangible Asset</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_SeveranceCosts1_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Severance Costs</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_SeveranceCosts1_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Severance and personnel expenses</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_CommitmentsToExtendCredit1Member_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Loan commitments are legally binding commitments to extend credit to a counterparty under certain terms and conditions.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_CommitmentsToExtendCredit1Member_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Commitments To Extend Credit1 [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_CommitmentsToExtendCredit1Member_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Commitments to Extend Credit [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_PercentageParValueAllowedAsCollateral_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Percentage par value allowed as collateral</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_PercentageParValueAllowedAsCollateral_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Percentage Par Value Allowed as Collateral</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_PercentageParValueAllowedAsCollateral_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Percentage par value allowed as collateral.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FairValueByBalanceSheetGroupingTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Fair Value, by Balance Sheet Grouping [Table Text Block]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FairValueByBalanceSheetGroupingTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Fair Value, by Balance Sheet Grouping</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipAxis_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Hedging Relationship [Axis]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipAxis_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Hedging Relationship</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="cyd_CybersecurityRiskThirdPartyOversightAndIdentificationProcessesFlag_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Cybersecurity Risk Third Party Oversight and Identification Processes [Flag]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_TreasuryStockPolicyTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Treasury stock policy text block.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_TreasuryStockPolicyTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Treasury Stock Policy [Text Block]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_TreasuryStockPolicyTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Treasury Stock</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_TierOneLeverageCapital_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Banking Regulation, Tier 1 Leverage Capital, Actual</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_TierOneLeverageCapital_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Tier 1 capital (to risk-weighted assets), Actual Regulatory Capital, Amount</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_QuarterlyFinancialInformationDisclosureAbstract_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Quarterly Financial Information Disclosure [Abstract]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ScheduleOfRestructuringAndRelatedCostsTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Restructuring and Related Costs [Table Text Block]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ScheduleOfRestructuringAndRelatedCostsTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Scheduled of Restructuring Charges</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DerivativeLineItems_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Derivative [Line Items]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DerivativeLineItems_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Derivative [Line Items]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_ActiveHedgesMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Active Hedges [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_ActiveHedgesMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Active Hedges [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_ActiveHedgesMember_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Active hedges.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_CashAndCashEquivalentsFairValueDisclosure_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Cash and Cash Equivalents, Fair Value Disclosure</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_CashAndCashEquivalentsFairValueDisclosure_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Cash and cash equivalents</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FinancingReceivables30To59DaysPastDueMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Financial Asset, 30 to 59 Days Past Due [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FinancingReceivables30To59DaysPastDueMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Financial Asset, 30 to 59 Days Past Due</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DeferredTaxAssetsValuationAllowance_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Deferred Tax Assets, Valuation Allowance</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DeferredTaxAssetsValuationAllowance_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Deferred tax valuation allowance</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_TableTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Table Text Block [Abstract]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_GoodwillAndOtherIntangibleAssetsLineItems_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Goodwill and other intangible assets.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_GoodwillAndOtherIntangibleAssetsLineItems_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Goodwill And Other Intangible Assets [Line Items]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_GoodwillAndOtherIntangibleAssetsLineItems_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Goodwill And Other Intangible Assets [Line Items]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_EffectiveIncomeTaxRateReconciliationAtFederalStatutoryIncomeTaxRate_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate, Percent</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_EffectiveIncomeTaxRateReconciliationAtFederalStatutoryIncomeTaxRate_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate, Percent</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_EffectiveIncomeTaxRateReconciliationAtFederalStatutoryIncomeTaxRate_lbl" xlink:role="http://www.xbrl.org/2003/role/verboseLabel">US federal statutory tax rate</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="stpr_AL_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Alabama [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="stpr_AL_lbl" xlink:role="http://www.xbrl.org/2003/role/label">ALABAMA</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_PledgedStatusAxis_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Pledged Status [Axis]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_IncomeTaxReconciliationNondeductibleExpense_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Effective Income Tax Rate Reconciliation, Nondeductible Expense, Amount</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_IncomeTaxReconciliationNondeductibleExpense_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Effective Income Tax Rate Reconciliation, Nondeductible Expense, Amount, Total</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_IncomeTaxReconciliationNondeductibleExpense_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Nontaxable or nondeductible items</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="cyd_CybersecurityRiskManagementThirdPartyEngagedFlag_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Cybersecurity Risk Management Third Party Engaged [Flag]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="dei_DocumentsIncorporatedByReferenceTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Documents Incorporated by Reference [Text Block]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="dei_DocumentsIncorporatedByReferenceTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Documents Incorporated by Reference</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_DeferredTaxLiabilitiesUnrealizedGainsOnCashFlowHedges_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Deferred tax liabilities unrealized gains on cash flow hedges.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_DeferredTaxLiabilitiesUnrealizedGainsOnCashFlowHedges_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Deferred Tax Liabilities Unrealized Gains on Cash Flow Hedges</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_DeferredTaxLiabilitiesUnrealizedGainsOnCashFlowHedges_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Unrealized gain on cash flow hedges</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_ForeclosedRealEstateOwnedFairValueLessDisposalCosts_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">The fair value less estimated costs to sell of foreclosed residential real estate held by the Company as of the balance sheet date.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_ForeclosedRealEstateOwnedFairValueLessDisposalCosts_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Foreclosed Real Estate Owned Fair Value Less Disposal Costs</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_ForeclosedRealEstateOwnedFairValueLessDisposalCosts_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Foreclosed real estate owned, fair value less disposal costs</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_Goodwill_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Goodwill</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_Goodwill_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Goodwill, Ending Balance</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_Goodwill_lbl" xlink:role="http://www.xbrl.org/2003/role/verboseLabel">Goodwill</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_Goodwill_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Goodwill, Total</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_Goodwill_lbl" xlink:role="http://www.xbrl.org/2003/role/periodStartLabel">Goodwill, Beginning Balance</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_Goodwill_lbl" xlink:role="http://www.xbrl.org/2003/role/periodEndLabel">Goodwill, Ending Balance</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_EffectiveIncomeTaxRateContinuingOperations_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Total</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_EffectiveIncomeTaxRateContinuingOperations_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Effective Income Tax Rate Reconciliation, Percent</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_EmployeeStockOptionMember_lbl" xlink:role="http://www.xbrl.org/2003/role/verboseLabel">Employee Stock Option [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_AllowanceForLoanAndLeaseLossesWriteOffsFiscalYearBeforeLatestFiscalYear_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Allowance For Loan And Lease Losses Write Offs Fiscal Year Before Latest Fiscal Year</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_AllowanceForLoanAndLeaseLossesWriteOffsFiscalYearBeforeLatestFiscalYear_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Allowance for loan and lease losses write offs fiscal year before latest fiscal year.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_AllowanceForLoanAndLeaseLossesWriteOffsFiscalYearBeforeLatestFiscalYear_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Current period gross charge-offs, 2024</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_IncomeTaxAuthorityAxis_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Income Tax Jurisdiction [Axis]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_IncomeTaxAuthorityAxis_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Income Tax Authority</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_TransferToOtherRealEstate_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Real Estate Owned, Transfer to Real Estate Owned</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_TransferToOtherRealEstate_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Additions</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_OtherRealEstateNetIncomeLoss_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Other real estate net income loss.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_OtherRealEstateNetIncomeLoss_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Other Real Estate Net Income Loss</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_OtherRealEstateNetIncomeLoss_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Net gains</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AvailableForSaleSecuritiesDebtMaturitiesAfterTenYearsAmortizedCost_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Debt Securities, Available-for-Sale, Amortized Cost, Maturity, Allocated and Single Maturity Date, after Year 10</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AvailableForSaleSecuritiesDebtMaturitiesAfterTenYearsAmortizedCost_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Available-for-sale, maturing after ten years, amortized cost</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DefinedContributionPlanEmployerMatchingContributionPercent_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Defined Contribution Plan, Employer Matching Contribution, Percent of Employees' Gross Pay</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DefinedContributionPlanEmployerMatchingContributionPercent_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Defined Contribution Plan, Employer Matching Contribution, Percent of Employees' Gross Pay</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_EquipmentFinancingLeasesMember_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Equipment financing leases member</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_EquipmentFinancingLeasesMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Equipment Financing Leases [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_EquipmentFinancingLeasesMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Equipment Financing Leases [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AdditionalPaidInCapitalCommonStock_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Additional Paid in Capital, Common Stock</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AdditionalPaidInCapitalCommonStock_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Additional paid-in capital</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FinancialInstrumentsFinancialLiabilitiesBalanceSheetGroupingsAbstract_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Financial Instruments, Financial Liabilities, Balance Sheet Groupings [Abstract]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FinancialInstrumentsFinancialLiabilitiesBalanceSheetGroupingsAbstract_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Liabilities:</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_StatementOfCashFlowsTable_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Statement of Cash Flows [Table]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_StatementOfCashFlowsTable_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Statement of cash flows table.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_OtherRealEstateGrossLosses_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Other real estate gross losses.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_OtherRealEstateGrossLosses_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Other Real Estate Gross Losses</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_OtherRealEstateGrossLosses_lbl" xlink:role="http://www.xbrl.org/2009/role/negatedLabel">Gross losses</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_HeldToMaturitySecuritiesDebtMaturitiesAfterTenYearsNetCarryingAmount_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Debt Securities, Held-to-Maturity, Amortized Cost, after Allowance for Credit Loss, Maturity, Allocated and Single Maturity Date, after Year 10</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_HeldToMaturitySecuritiesDebtMaturitiesAfterTenYearsNetCarryingAmount_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Held-to-maturity, maturing after ten years, amortized cost</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_RelatedPartyMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Related Party [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_NumberOfStates_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Number of states conducting lending of loan portfolio.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_NumberOfStates_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Number Of States</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_NumberOfStates_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Number of states</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_SecuredByNonResidentialCommercialRealEstateMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Secured By Non Residential Commercial Real Estate [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_SecuredByNonResidentialCommercialRealEstateMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Secured By Non Residential Commercial Real Estate [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_SecuredByNonResidentialCommercialRealEstateMember_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Secured by non residential commercial real estate.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_SecuredByNonResidentialCommercialRealEstateMember_lbl" xlink:role="http://www.xbrl.org/2003/role/verboseLabel">Secured by Non-residential Commercial Real Estate [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_SignificantAccountingPoliciesTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Significant Accounting Policies [Text Block]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_SignificantAccountingPoliciesTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Summary of Significant Accounting Policies</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_PropertyPlantAndEquipmentLineItems_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Property, Plant and Equipment [Line Items]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_PropertyPlantAndEquipmentLineItems_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Property Plant And Equipment [Line Items]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_NonperformingFinancingReceivableMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Nonperforming Financial Instruments</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_NonperformingFinancingReceivableMember_lbl" xlink:role="http://www.xbrl.org/2003/role/verboseLabel">Non-performing [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_NonperformingFinancingReceivableMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Nonperforming Financial Instruments [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_ReclassificationOfUnrealizedGainsOnTerminatedDerivativeContracts_lbl" xlink:role="http://www.xbrl.org/2009/role/negatedLabel">Reclassification of unrealized gains on terminated derivative contracts</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_ReclassificationOfUnrealizedGainsOnTerminatedDerivativeContracts_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Reclassification of unrealized gains on terminated derivative contracts</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_ReclassificationOfUnrealizedGainsOnTerminatedDerivativeContracts_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Reclassification of unrealized gains on terminated derivative contracts</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FiniteLivedIntangibleAssetUsefulLife_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Finite-Lived Intangible Asset, Useful Life</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FiniteLivedIntangibleAssetUsefulLife_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Finite-lived intangible asset, useful life</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_GainsLossesOnSalesOfPremisesEquipmentAndOtherRealEstateHeldForSale_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Gains losses on sales of premises equipment and other real estate held for sale.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_GainsLossesOnSalesOfPremisesEquipmentAndOtherRealEstateHeldForSale_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Gains Losses On Sales Of Premises Equipment And Other Real Estate Held For Sale</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_GainsLossesOnSalesOfPremisesEquipmentAndOtherRealEstateHeldForSale_lbl" xlink:role="http://www.xbrl.org/2009/role/negatedLabel">Net loss on premises and equipment and other real estate</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodGross_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Grants in Period, Gross</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodGross_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Granted (in shares)</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodGross_lbl" xlink:role="http://www.xbrl.org/2003/role/verboseLabel">Granted (in shares)</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DepositsFairValueDisclosure_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Deposits, Fair Value Disclosure</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DepositsFairValueDisclosure_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Deposits</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="cyd_CybersecurityRiskManagementStrategyAndGovernanceTable_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Cybersecurity Risk Management, Strategy, and Governance [Table]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ScheduleOfEarningsPerShareBasicAndDilutedTableTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Schedule of Earnings Per Share, Basic and Diluted [Table Text Block]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ScheduleOfEarningsPerShareBasicAndDilutedTableTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Schedule of Earnings Per Share, Basic and Diluted</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_NetInvestmentHedgingMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Net Investment Hedging [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_IncreaseDecreaseInOtherOperatingCapitalNet_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Increase (Decrease) in Other Operating Assets and Liabilities, Net</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_IncreaseDecreaseInOtherOperatingCapitalNet_lbl" xlink:role="http://www.xbrl.org/2009/role/negatedLabel">Change in other assets and liabilities</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_IncreaseDecreaseInOtherOperatingCapitalNet_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Increase (Decrease) in Other Operating Assets and Liabilities, Net, Total</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_SpecialMentionMember_lbl" xlink:role="http://www.xbrl.org/2003/role/verboseLabel">Special Mention [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_SpecialMentionMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Special Mention</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_SpecialMentionMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Special Mention [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_InvestmentsClassifiedByContractualMaturityDateTableTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Investments Classified by Contractual Maturity Date [Table Text Block]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_InvestmentsClassifiedByContractualMaturityDateTableTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Maturities of Investment Securities Available-for-Sale and Held-to-Maturity</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_EarningsPerShareBasic_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Earnings Per Share, Basic</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_EarningsPerShareBasic_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Basic net income per share</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_EarningsPerShareBasic_lbl" xlink:role="http://www.xbrl.org/2003/role/verboseLabel">Basic earnings</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_EarningsPerShareBasic_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Earnings Per Share, Basic, Total</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_NumberOfInterestRateSwapContracts_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Number of interest rate swap contracts</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_NumberOfInterestRateSwapContracts_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Number Of Interest Rate Swap Contracts</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_NumberOfInterestRateSwapContracts_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Number of interest rate swap contracts.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_HeldToMaturitySecuritiesAccumulatedUnrecognizedHoldingGain_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Debt Securities, Held-to-Maturity, Accumulated Unrecognized Gain</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_HeldToMaturitySecuritiesAccumulatedUnrecognizedHoldingGain_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Held-to-maturity, gross unrealized gains</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_InvestmentInFederalHomeLoanBankStockFairValueDisclosure_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Investment in Federal Home Loan Bank Stock, Fair Value Disclosure</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_InvestmentInFederalHomeLoanBankStockFairValueDisclosure_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Federal Home Loan Bank stock</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_PensionAndOtherPostretirementBenefitsDisclosureTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Retirement Benefits [Text Block]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_PensionAndOtherPostretirementBenefitsDisclosureTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Employee Benefit Plans</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_OtherComprehensiveIncomeLossReclassificationAdjustmentNetGainsOnCashFlowHedgeDerivativesRealizedInNetIncomeNetOfTax_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Other comprehensive income (loss), reclassification adjustment net gains on cash flow hedge derivatives realized in net income, net of tax.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_OtherComprehensiveIncomeLossReclassificationAdjustmentNetGainsOnCashFlowHedgeDerivativesRealizedInNetIncomeNetOfTax_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Other comprehensive income (loss), reclassification adjustment net gains on cash flow hedge derivatives realized in net income, net of tax</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_OtherComprehensiveIncomeLossReclassificationAdjustmentNetGainsOnCashFlowHedgeDerivativesRealizedInNetIncomeNetOfTax_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Reclassification adjustments on cash flow hedge derivatives realized in net income, net of tax benefit of $48 and $112, respectively</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_InterestRateCapOneMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Interest Rate Cap One [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_InterestRateCapOneMember_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Interest rate cap one.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_AllowanceForLoanAndLeaseLossesWriteOffsThreeYearsBeforeLatestFiscalYear_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Allowance for Loan and Lease Losses Write Offs Three Years Before Latest Fiscal Year</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_AllowanceForLoanAndLeaseLossesWriteOffsThreeYearsBeforeLatestFiscalYear_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Allowance for loan and lease losses write offs three years before latest fiscal year.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_AllowanceForLoanAndLeaseLossesWriteOffsThreeYearsBeforeLatestFiscalYear_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Current period gross charge-offs, 2022</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_CommercialPortfolioSegmentMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Commercial [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_CommercialPortfolioSegmentMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Commercial Portfolio Segment [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Outstanding, Number</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber_lbl" xlink:role="http://www.xbrl.org/2003/role/periodEndLabel">Options outstanding, end of year (in shares)</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber_lbl" xlink:role="http://www.xbrl.org/2003/role/periodStartLabel">Outstanding, beginning of year (in shares)</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_NoninterestExpenseDirectorsFees_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Directors fees</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_NoninterestExpenseDirectorsFees_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Director Fee</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ReinsuranceAccountingPolicy_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Reinsurance Accounting Policy [Policy Text Block]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ReinsuranceAccountingPolicy_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Reinsurance Activities</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsReleasedFromRestrictionInPeriod_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Share based compensation arrangement by share based payment award, equity instruments other than options, released from restriction in period</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsReleasedFromRestrictionInPeriod_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Share-based compensation arrangement by share-based payment award equity instruments other than options released from restriction in period.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsReleasedFromRestrictionInPeriod_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Released from restriction (in shares)</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_OperatingLeaseLeaseIncome_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Operating Lease, Lease Income</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_OperatingLeaseLeaseIncome_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Operating lease income</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_OperatingLeaseLeaseIncome_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Operating Lease, Lease Income, Total</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Adjustment to Reconcile Net Income to Cash Provided by (Used in) Operating Activity [Abstract]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Adjustments to reconcile net income to cash provided by operating activities:</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract_lbl" xlink:role="http://www.xbrl.org/2003/role/verboseLabel">Adjustments to reconcile net income to net cash provided by operating activities:</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearFive_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Lessee, Operating Lease, Liability, to be Paid, Year Five</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearFive_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">2029</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_HedgingDesignationDomain_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Hedging Designation</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_HedgingDesignationDomain_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Hedging Designation [Domain]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DerivativeInstrumentsAndHedgesLiabilities_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Derivative Instruments and Hedges, Liabilities</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DerivativeInstrumentsAndHedgesLiabilities_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Derivative Instruments and Hedges, Liabilities, Total</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DerivativeInstrumentsAndHedgesLiabilities_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Derivative instruments and hedges, cash payment</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_IncomeTaxPaidFederalAfterRefundReceived_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Income Tax Paid, Federal, after Refund Received</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_IncomeTaxPaidFederalAfterRefundReceived_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Income Tax Paid, Federal, after Refund Received, Total</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_IncomeTaxPaidFederalAfterRefundReceived_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Federal</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_PledgingPurposeAxis_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Pledging Purpose [Axis]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_InterestIncomeDepositsWithFinancialInstitutions_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Interest on deposits in banks</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_InterestIncomeDepositsWithFinancialInstitutions_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Interest Income, Deposits with Financial Institutions</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_InterestIncomeDepositsWithFinancialInstitutions_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Interest Income, Deposits with Financial Institutions, Total</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DomesticCountryMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Domestic Tax Jurisdiction [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DomesticCountryMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Federal [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FinancingReceivableAllowanceForCreditLossesLineItems_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Financing Receivable, Allowance for Credit Loss [Line Items]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_LesseeOperatingLeaseRemainingTermOfContract_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">The remaining term of lessee's operating lease, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_LesseeOperatingLeaseRemainingTermOfContract_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Lessee Operating Lease Remaining Term Of Contract</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_LesseeOperatingLeaseRemainingTermOfContract_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Lessee, Operating Lease, Remaining Term of Contract</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AdjustmentsForNewAccountingPronouncementsAxis_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Accounting Standards Update [Axis]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="srt_ConsolidationItemsDomain_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Consolidation Items [Domain]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="srt_ConsolidationItemsDomain_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Consolidation Items</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_MortgageBankingMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Mortgage Banking [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_MortgageBankingMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Mortgage Banking [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_StockholdersEquityAbstract_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Equity, Attributable to Parent [Abstract]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_StockholdersEquityAbstract_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Shareholders&#8217; equity:</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="dei_EntitySmallBusiness_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Entity Small Business</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="dei_EntitySmallBusiness_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Entity Small Business</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_TimeDepositMaturitiesAfterYearFour_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Time Deposit Maturities After Year Four</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_TimeDepositMaturitiesAfterYearFour_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Time deposit maturities after year four.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_TimeDepositMaturitiesAfterYearFour_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">2029 and after</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_InterestAndDividendIncomeOperatingAbstract_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Interest and Dividend Income, Operating [Abstract]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_InterestAndDividendIncomeOperatingAbstract_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Interest income:</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FederalFundsPurchasedAndSecuritiesSoldUnderAgreementsToRepurchaseMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Federal Funds Sold and Securities Purchased under Reverse Repurchase Agreements [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FederalFundsPurchasedAndSecuritiesSoldUnderAgreementsToRepurchaseMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Federal Funds Purchased and Securities Sold under Agreements to Repurchase [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_HedgingDesignationAxis_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Hedging Designation [Axis]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_HedgingDesignationAxis_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Hedging Designation</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_RetainedEarningsAccumulatedDeficit_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Retained Earnings (Accumulated Deficit)</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_RetainedEarningsAccumulatedDeficit_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Retained earnings</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_RetainedEarningsAccumulatedDeficit_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Retained Earnings (Accumulated Deficit), Total</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ScheduleOfFinancingReceivablesNonAccrualStatusTableTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Financing Receivable, Nonaccrual [Table Text Block]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ScheduleOfFinancingReceivablesNonAccrualStatusTableTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Non-accruing Loans</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_AllowanceForLoanAndLeaseLossesWriteOffsFiveOrMoreYearsBeforeLatestFiscalYear_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Current period gross charge-offs, Prior</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_AllowanceForLoanAndLeaseLossesWriteOffsFiveOrMoreYearsBeforeLatestFiscalYear_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Allowance For Loan And Lease Losses Write Offs Five Or More Years Before Latest Fiscal Year</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_AllowanceForLoanAndLeaseLossesWriteOffsFiveOrMoreYearsBeforeLatestFiscalYear_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Allowance for loan and lease losses write offs five or more years before latest fiscal year.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_NatureOfOperations_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Nature of Operations [Text Block]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_NatureOfOperations_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Description of Business</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DebtSecuritiesHeldToMaturityAllowanceForCreditLoss_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Debt Securities, Held-to-Maturity, Allowance for Credit Loss</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DebtSecuritiesHeldToMaturityAllowanceForCreditLoss_lbl" xlink:role="http://www.xbrl.org/2003/role/periodEndLabel">Debt Securities, Held-to-Maturity, Allowance for Credit Loss, Ending Balance</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DebtSecuritiesHeldToMaturityAllowanceForCreditLoss_lbl" xlink:role="http://www.xbrl.org/2003/role/periodStartLabel">Debt Securities, Held-to-Maturity, Allowance for Credit Loss, Beginning Balance</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DebtSecuritiesHeldToMaturityAllowanceForCreditLoss_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Debt Securities, Held-to-Maturity, Allowance for Credit Loss, Total</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DebtSecuritiesHeldToMaturityAllowanceForCreditLoss_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Held to maturity, allowance for credit losses</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DebtSecuritiesHeldToMaturityAllowanceForCreditLoss_lbl" xlink:role="http://www.xbrl.org/2003/role/verboseLabel">Held-to-maturity securities allowance for credit loss</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="dei_EntityWellKnownSeasonedIssuer_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Entity Well-known Seasoned Issuer</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="dei_EntityWellKnownSeasonedIssuer_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Entity Well-known Seasoned Issuer</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_CollateralDependentLoansMeasurementInput_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Collateral dependent loans</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_CollateralDependentLoansMeasurementInput_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Collateral Dependent Loans Measurement Input</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_CollateralDependentLoansMeasurementInput_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Collateral dependent loans measurement input.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_FinancingReceivableAllowanceForCreditLossWriteoffAfterRecoveryLineItems_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Financing Receivable, Allowance for Credit Loss, Writeoff, after Recovery [Line Items]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_FinancingReceivableAllowanceForCreditLossWriteoffAfterRecoveryLineItems_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Financing receivable, allowance for credit loss, writeoff, after recovery.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsForfeituresInPeriod_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Forfeitures in Period</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsForfeituresInPeriod_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Forfeited (in shares)</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AllowanceForCreditLossAbstract_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Allowance for Credit Loss [Abstract]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DerivativeInceptionDates_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Derivative, Inception Date</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DerivativeInceptionDates_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Derivative, start date</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DisclosureOfCompensationRelatedCostsShareBasedPaymentsTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Share-Based Payment Arrangement [Text Block]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DisclosureOfCompensationRelatedCostsShareBasedPaymentsTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Stock Awards</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_OrganizationConsolidationAndPresentationOfFinancialStatementsAbstract_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Organization, Consolidation and Presentation of Financial Statements [Abstract]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_IncomeTaxDisclosureTable_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Income Tax Disclosure [Table]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_IncomeTaxDisclosureTable_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Income tax disclosure.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_PaymentsOfDividends_lbl" xlink:role="http://www.xbrl.org/2009/role/negatedLabel">Dividends paid</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_PaymentsOfDividends_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Payments of Dividends</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_PaymentsOfDividends_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Payments of Dividends, Total</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_OtherRealEstateOtherAssetsFairValueDisclosure_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Other real estate and other assets held-for-sale.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_OtherRealEstateOtherAssetsFairValueDisclosure_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Other Real Estate Other Assets Fair Value Disclosure</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_OtherRealEstateOtherAssetsFairValueDisclosure_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">OREO and other assets held-for-sale</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_OtherRealEstateOtherAssetsFairValueDisclosure_lbl" xlink:role="http://www.xbrl.org/2003/role/verboseLabel">OREO and other assets held-for-sale</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LeasesAbstract_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Leases [Abstract]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_RestructuringAndRelatedCostExpectedCostRemaining1_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Restructuring and Related Cost, Expected Cost Remaining</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_RestructuringAndRelatedCostExpectedCostRemaining1_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Restructuring charges expects to incur</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_CreditRiskParticipationAgreementsMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Credit Risk Participation Agreements [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_CreditRiskParticipationAgreementsMember_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Credit risk participation agreements.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_CreditRiskParticipationAgreementsMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Credit Risk Participation Agreements [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_WeightedAverageNumberDilutedSharesOutstandingAdjustment_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Weighted Average Number of Shares Outstanding, Diluted, Adjustment</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_WeightedAverageNumberDilutedSharesOutstandingAdjustment_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Dilutive shares</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_WeightedAverageNumberDilutedSharesOutstandingAdjustment_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Weighted Average Number of Shares Outstanding, Diluted, Adjustment, Total</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LesseeLeaseDescriptionLineItems_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Lessee, Lease, Description [Line Items]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LesseeLeaseDescriptionLineItems_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Lessee Lease Description [Line Items]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="dei_AmendmentFlag_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Amendment Flag</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="dei_AmendmentFlag_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Amendment Flag</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ImpairmentOfRealEstate_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Impairment of Real Estate</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ImpairmentOfRealEstate_lbl" xlink:role="http://www.xbrl.org/2009/role/negatedLabel">Impairment</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_InterestIncomeSecuritiesTaxable_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Interest Income, Securities, Operating, Taxable</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_InterestIncomeSecuritiesTaxable_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Taxable</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="srt_ProductsAndServicesDomain_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Product and Service [Domain]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="srt_ProductsAndServicesDomain_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Product and Service</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LossContingenciesLineItems_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Loss Contingencies [Line Items]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ScheduleOfOtherOperatingCostAndExpenseByComponentTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Schedule of Other Operating Cost and Expense, by Component [Table Text Block]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ScheduleOfOtherOperatingCostAndExpenseByComponentTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Other Operating Expense</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_IncomeTaxReconciliationIncomeTaxExpenseBenefitAtFederalStatutoryIncomeTaxRate_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Effective Income Tax Rate Reconciliation at Federal Statutory Income Tax Rate, Amount</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_IncomeTaxReconciliationIncomeTaxExpenseBenefitAtFederalStatutoryIncomeTaxRate_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Income tax expense at federal statutory rate</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_RestructuredLoanModifiedThroughExtendedMaturityAndPaymentScheduleModificationMember_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Member stands for restructured loan modified through extended maturity and payment schedule modification.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_RestructuredLoanModifiedThroughExtendedMaturityAndPaymentScheduleModificationMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Restructured Loan Modified Through Extended Maturity And Payment Schedule Modification [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_RestructuredLoanModifiedThroughExtendedMaturityAndPaymentScheduleModificationMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Restructured Loan Modified through Extended Maturity and Payment Schedule Modification [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FederalFundsSoldAndSecuritiesPurchasedUnderAgreementsToResell_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Federal Funds Sold and Securities Purchased under Agreements to Resell</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FederalFundsSoldAndSecuritiesPurchasedUnderAgreementsToResell_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Federal Funds Sold and Securities Purchased under Agreements to Resell, Total</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FederalFundsSoldAndSecuritiesPurchasedUnderAgreementsToResell_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Federal funds sold and securities purchased under reverse repurchase agreements</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_EarningsPerSharePolicyTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Earnings Per Share, Policy [Policy Text Block]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_EarningsPerSharePolicyTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Net Income Per Share</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LiabilitiesAndStockholdersEquityAbstract_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Liabilities and Equity [Abstract]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LiabilitiesAndStockholdersEquityAbstract_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">LIABILITIES AND SHAREHOLDERS&#8217; EQUITY</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="dei_EntityAddressPostalZipCode_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Entity Address, Postal Zip Code</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="dei_EntityAddressPostalZipCode_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Entity Address, Postal Zip Code</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_NumberOfFullTimeEmployees_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Number of full time employees</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_NumberOfFullTimeEmployees_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Number Of Full Time Employees</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_NumberOfFullTimeEmployees_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Number of full time employees</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_NetCashProvidedByUsedInOperatingActivities_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Cash Provided by (Used in) Operating Activity, Including Discontinued Operation</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_NetCashProvidedByUsedInOperatingActivities_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Net cash provided by operating activities</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_SubstandardMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Substandard [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_SubstandardMember_lbl" xlink:role="http://www.xbrl.org/2003/role/verboseLabel">Substandard</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_SubstandardMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Substandard [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_ForeclosedRealEstateOtherExpenseNetOfGainOrLossOnSale_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Foreclosed real estate other expense net of gain or loss on sale.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_ForeclosedRealEstateOtherExpenseNetOfGainOrLossOnSale_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Foreclosed Real Estate Other Expense Net Of Gain Or Loss On Sale</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_ForeclosedRealEstateOtherExpenseNetOfGainOrLossOnSale_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Other real estate/foreclosure expense, net</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_SegmentReportingCodmProfitLossMeasureHowUsedDescription_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Segment Reporting, CODM, Profit (Loss) Measure, How Used, Description</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_InterestRateSwapOneMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Interest Rate Swap One [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_InterestRateSwapOneMember_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Interest rate swap one.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_CommonStockMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Common Stock [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_CommonStockMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Common Stock [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AllowanceForLoanAndLeaseLossesWriteoffsNetAbstract_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Financing Receivable, Allowance for Credit Loss, Writeoff, after Recovery [Abstract]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="cyd_CybersecurityRiskRoleOfManagementTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Cybersecurity Risk Role of Management [Text Block]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DefinedContributionPlanEmployerDiscretionaryContributionAmount_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Defined Contribution Plan, Employer Discretionary Contribution Amount</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DefinedContributionPlanEmployerDiscretionaryContributionAmount_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Defined Contribution Plan, Employer Discretionary Contribution Amount</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_GainOnSalesOfPremisesAndEquipmentAndOtherAssets_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Gain on sales of premises and equipment and other assets.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_GainOnSalesOfPremisesAndEquipmentAndOtherAssets_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Gain On Sales Of Premises And Equipment And Other Assets</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_GainOnSalesOfPremisesAndEquipmentAndOtherAssets_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Gain on sales of premises and equipment and other assets</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageExercisePrice_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Share-Based Compensation Arrangements by Share-Based Payment Award, Options, Grants in Period, Weighted Average Exercise Price</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageExercisePrice_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Granted, weighted average exercise price (in dollars per share)</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_HedgingRelationshipDomain_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Hedging Relationship [Domain]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_HedgingRelationshipDomain_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Hedging Relationship</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ScheduleOfComplianceWithRegulatoryCapitalRequirementsUnderBankingRegulationsTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Schedule of Compliance with Regulatory Capital Requirements under Banking Regulations [Table Text Block]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ScheduleOfComplianceWithRegulatoryCapitalRequirementsUnderBankingRegulationsTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Schedule of Compliance with Regulatory Capital Requirements under Banking Regulations</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearThree_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">2028</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearThree_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Lessee, Operating Lease, Liability, to be Paid, Year Three</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Accumulated Depreciation, Depletion and Amortization, Property, Plant, and Equipment</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Accumulated depreciation</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment_lbl" xlink:role="http://www.xbrl.org/2009/role/negatedLabel">Less accumulated depreciation</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Accumulated Depreciation, Depletion and Amortization, Property, Plant, and Equipment, Total</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment_lbl" xlink:role="http://www.xbrl.org/2003/role/periodStartLabel">Accumulated Depreciation, Depletion and Amortization, Property, Plant, and Equipment, Beginning Balance</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment_lbl" xlink:role="http://www.xbrl.org/2003/role/periodEndLabel">Accumulated Depreciation, Depletion and Amortization, Property, Plant, and Equipment, Ending Balance</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DividendIncomeOperating_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Dividend Income, Operating</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DividendIncomeOperating_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Dividend income, First US Bank</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DividendIncomeOperating_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Dividend Income, Operating, Total</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ScheduleOfDerivativeInstrumentsInStatementOfFinancialPositionFairValueTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Schedule of Derivative Instruments in Statement of Financial Position, Fair Value [Table Text Block]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ScheduleOfDerivativeInstrumentsInStatementOfFinancialPositionFairValueTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Schedule of Cumulative Basis Adjustments for Fair Value Hedges</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AmortizationOfDebtDiscountPremium_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Amortization of Debt Discount (Premium)</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AmortizationOfDebtDiscountPremium_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Net accretion of securities</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_IncomeTaxPaidByIndividualJurisdictionLineItems_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Income Tax Paid, by Individual Jurisdiction [Line Items]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_PortionAtFairValueFairValueDisclosureMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Portion at Fair Value Measurement [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_PortionAtFairValueFairValueDisclosureMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Fair Value Disclosure Item Amounts [Default]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_PortionAtFairValueFairValueDisclosureMember_lbl" xlink:role="http://fasb.org/us-gaap/role/label/axisDefault">Portion at Fair Value Measurement [Member] [Default]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="dei_EntityAddressAddressLine1_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Entity Address, Address Line One</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="dei_EntityAddressAddressLine1_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Entity Address, Address Line One</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DeferredIncomeTaxLiabilities_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Deferred Tax Liabilities, Gross</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DeferredIncomeTaxLiabilities_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Total gross deferred tax liabilities</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_LesseeOperatingLeaseLiabilityToBePaidAfterYearFour_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Lessee, operating lease, liability, to be paid, after year four.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_LesseeOperatingLeaseLiabilityToBePaidAfterYearFour_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">2030 and thereafter</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_LesseeOperatingLeaseLiabilityToBePaidAfterYearFour_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Lessee, Operating Lease, Liability, to be Paid, after Year Four</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FairValueByFairValueHierarchyLevelAxis_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Fair Value Hierarchy and NAV [Axis]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FairValueByFairValueHierarchyLevelAxis_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Fair Value, Inputs, Level 2 [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ShorttermDebtFairValue_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Short-Term Debt, Fair Value</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ShorttermDebtFairValue_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Short-term borrowings</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_EarningsPerShareAbstract_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Earnings Per Share [Abstract]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_IncomeTaxPolicyTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Income Tax, Policy [Policy Text Block]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_IncomeTaxPolicyTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Income Taxes</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="cyd_CybersecurityRiskMateriallyAffectedOrReasonablyLikelyToMateriallyAffectRegistrantFlag_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Cybersecurity Risk Materially Affected or Reasonably Likely to Materially Affect Registrant [Flag]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ConsumerPortfolioSegmentMember_lbl" xlink:role="http://www.xbrl.org/2003/role/verboseLabel">Consumer [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ConsumerPortfolioSegmentMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Consumer Portfolio Segment [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ConsumerPortfolioSegmentMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Consumer Portfolio Segment [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_BranchRetailMember_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Represents branch retail loans.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_BranchRetailMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Branch Retail [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_BranchRetailMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Branch Retail [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DerivativeAssets_lbl" xlink:role="http://www.xbrl.org/2003/role/verboseLabel">Other assets - derivatives</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DerivativeAssets_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Derivative Asset</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DerivativeAssets_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Other assets ? derivatives</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DerivativeAssets_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Derivative Asset, Total</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_GoodwillAndIntangibleAssetsDisclosureTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Goodwill and Intangible Assets Disclosure [Text Block]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_GoodwillAndIntangibleAssetsDisclosureTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Goodwill and Other Intangible Assets</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_TierOneLeverageCapitalToAverageAssets_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Banking Regulation, Tier 1 Leverage Capital Ratio, Actual</link:label>
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          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_FederalHomeLoanBankAdvancesGeneralDebtObligationsDisclosuresExcessOfCollateralAvailableToUtilizeAdditionalCredit_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Amount of collateral pledged in excess available to utilize additional credit.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_FederalHomeLoanBankAdvancesGeneralDebtObligationsDisclosuresExcessOfCollateralAvailableToUtilizeAdditionalCredit_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Federal Home Loan Bank Advances General Debt Obligations Disclosures Excess Of Collateral Available To Utilize Additional Credit</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_FederalHomeLoanBankAdvancesGeneralDebtObligationsDisclosuresExcessOfCollateralAvailableToUtilizeAdditionalCredit_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Collateral pledged in excess available to utilize additional credit</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_OtherLiabilitiesMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Other Liabilities [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_OtherLiabilitiesMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Other Liabilities [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_OtherNonInterestIncomeMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Other Non-Interest Income [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_OtherNonInterestIncomeMember_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Other non-interest income member.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_OtherNonInterestIncomeMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Other Non-Interest Income [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_BalanceSheetLocationAxis_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Statement of Financial Position Location, Balance [Axis]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_BalanceSheetLocationAxis_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Balance Sheet Location</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_InterestIncomeSecuritiesTaxExempt_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Interest Income, Securities, Operating, Tax Exempt</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_InterestIncomeSecuritiesTaxExempt_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Tax-exempt</link:label>
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          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_OperatingLeaseRightOfUseAsset_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Operating Lease, Right-of-Use Asset</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_OperatingLeaseRightOfUseAsset_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Operating lease right-of-use assets</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DeferredTaxAssetsGross_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Deferred Tax Assets, Gross</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DeferredTaxAssetsGross_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Total gross deferred tax assets</link:label>
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          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_CommitmentRequiredForEvaluatingIndividuallyAtManagementDiscretion_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Commitment Required for Evaluating Individually At Management Discretion</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_CommitmentRequiredForEvaluatingIndividuallyAtManagementDiscretion_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Commitment required for evaluating individually at management discretion.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="cyd_CybersecurityRiskBoardCommitteeOrSubcommitteeResponsibleForOversightTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Cybersecurity Risk Board Committee or Subcommittee Responsible for Oversight [Text Block]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_PaymentsToAcquireAvailableForSaleSecuritiesDebt_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Payments to Acquire Debt Securities, Available-for-Sale</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_PaymentsToAcquireAvailableForSaleSecuritiesDebt_lbl" xlink:role="http://www.xbrl.org/2009/role/negatedLabel">Purchases of investment securities, available-for-sale</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_OtherComprehensiveIncomeLossAvailableForSaleSecuritiesAdjustmentNetOfTax_lbl" xlink:role="http://www.xbrl.org/2003/role/label">OCI, Debt Securities, Available-for-Sale, Gain (Loss), after Adjustment and Tax</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_OtherComprehensiveIncomeLossAvailableForSaleSecuritiesAdjustmentNetOfTax_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Net change in fair value of securities available-for-sale, net of tax</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_OtherComprehensiveIncomeLossAvailableForSaleSecuritiesAdjustmentNetOfTax_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">OCI, Debt Securities, Available-for-Sale, Gain (Loss), after Adjustment and Tax, Total</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_MeasurementInputComparabilityAdjustmentMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Measurement Input, Comparability Adjustment [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_MeasurementInputComparabilityAdjustmentMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Measurement Input, Comparability Adjustment [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_ImpairedLoansMeasurementInput_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Fair value portion of impaired loans by an entity as a result of past transactions or events.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_ImpairedLoansMeasurementInput_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Impaired Loans Measurement Input</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_ImpairedLoansMeasurementInput_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Impaired loans</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="dei_DocumentType_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Document Type</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="dei_DocumentType_lbl" xlink:role="http://www.xbrl.org/2003/role/verboseLabel">Document Type</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_SecuredByNonfarmNonresidentialPropertiesMember_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Represents information pertaining to loans secured by non-farm, non-residential properties.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_SecuredByNonfarmNonresidentialPropertiesMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Secured By Nonfarm Nonresidential Properties [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_SecuredByNonfarmNonresidentialPropertiesMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Secured By Non-farm Non residential Properties [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FinancingReceivableIndividuallyEvaluatedForImpairment_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Financing Receivable, Individually Evaluated for Credit Loss</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FinancingReceivableIndividuallyEvaluatedForImpairment_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Individually evaluated for impairment</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_IncomeTaxesPaidNet_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Income Taxes Paid, Net</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_IncomeTaxesPaidNet_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Income taxes</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_IncomeTaxesPaidNet_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Total</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_IncomeTaxesPaidNet_lbl" xlink:role="http://www.xbrl.org/2003/role/verboseLabel">Total taxes</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="dei_EntityCentralIndexKey_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Entity Central Index Key</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="dei_EntityCentralIndexKey_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Entity Central Index Key</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_InvestmentsDebtAndEquitySecuritiesAbstract_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Investments, Debt and Equity Securities [Abstract]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="cyd_CybersecurityRiskProcessForInformingBoardCommitteeOrSubcommitteeResponsibleForOversightTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Cybersecurity Risk Process for Informing Board Committee or Subcommittee Responsible for Oversight [Text Block]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_InterestBearingDepositsInBanks_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Interest-Bearing Deposits in Banks and Other Financial Institutions</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_InterestBearingDepositsInBanks_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Interest-bearing deposits in banks</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LoansAndLeasesReceivableRelatedParties_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Loans and Leases Receivable, Related Parties</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LoansAndLeasesReceivableRelatedParties_lbl" xlink:role="http://www.xbrl.org/2003/role/periodEndLabel">Loans and Leases Receivable, Related Parties, Ending Balance</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LoansAndLeasesReceivableRelatedParties_lbl" xlink:role="http://www.xbrl.org/2003/role/periodStartLabel">Loans and Leases Receivable, Related Parties, Beginning Balance</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Cash, Cash Equivalent, Restricted Cash, and Restricted Cash Equivalent, Period Increase (Decrease), Including Exchange Rate Effect and Discontinued Operation</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Net increase (decrease) in cash and cash equivalents</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_SubsequentEventTypeDomain_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Subsequent Event Type [Domain]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_InterestIncomeOperating_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Interest Income, Operating</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_InterestIncomeOperating_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Interest Income, Operating, Total</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_InterestIncomeOperating_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Interest income</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_IntangibleAssetsNetIncludingGoodwill_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Intangible Assets, Net (Including Goodwill)</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_IntangibleAssetsNetIncludingGoodwill_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Goodwill and core deposit intangible, net</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_IntangibleAssetsNetIncludingGoodwill_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Total</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="srt_ScheduleOfCondensedBalanceSheetTableTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Condensed Balance Sheet [Table Text Block]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="srt_ScheduleOfCondensedBalanceSheetTableTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Balance Sheet</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_BalanceSheetRelatedDisclosuresAbstract_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Balance Sheet Related Disclosures [Abstract]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DeferredCompensationArrangementWithIndividualCommonStockReservedForFutureIssuance_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Deferred Compensation Arrangement with Individual, Common Stock Reserved for Future Issuance</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DeferredCompensationArrangementWithIndividualCommonStockReservedForFutureIssuance_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Deferred Compensation Arrangement with Individual, Common Stock Reserved for Future Issuance</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_StockRepurchasedAndRetiredDuringPeriodShares_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Stock Repurchased and Retired During Period, Shares</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_StockRepurchasedAndRetiredDuringPeriodShares_lbl" xlink:role="http://www.xbrl.org/2009/role/negatedLabel">Impact of common stock share repurchases (in shares)</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_HeldToMaturitySecuritiesDebtMaturitiesAfterFiveThroughTenYearsNetCarryingAmount_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Debt Securities, Held-to-Maturity, Amortized Cost, after Allowance for Credit Loss, Maturity, Allocated and Single Maturity Date, after Year 5 through 10</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_HeldToMaturitySecuritiesDebtMaturitiesAfterFiveThroughTenYearsNetCarryingAmount_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Held-to-maturity, maturing after five to ten years, amortized cost</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ShortTermDebtTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Short-Term Debt [Text Block]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ShortTermDebtTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Borrowings</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_CommonStockParOrStatedValuePerShare_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Common Stock, Par or Stated Value Per Share</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_CommonStockParOrStatedValuePerShare_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Common stock, par value (in dollars per share)</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_TypeOfAdoptionMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Accounting Standards Update [Domain]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_CommonEquityTierOneCapital_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Banking Regulation, Common Equity Tier 1 Risk-Based Capital, Actual</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_CommonEquityTierOneCapital_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Common equity Tier 1 capital (to risk-weighted assets), Actual Regulatory Capital, Amount</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_OtherThanTemporaryImpairmentLossDebtSecuritiesAvailableForSaleRecognizedInEarningsInterestRate_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Other than temporary impairment loss debt securities available for sale recognized in earnings interest rate.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_OtherThanTemporaryImpairmentLossDebtSecuritiesAvailableForSaleRecognizedInEarningsInterestRate_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Other Than Temporary Impairment Loss Debt Securities Available For Sale Recognized In Earnings Interest Rate</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_OtherThanTemporaryImpairmentLossDebtSecuritiesAvailableForSaleRecognizedInEarningsInterestRate_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Other than temporary impairment loss debt securities available for sale interest rate</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_PaycheckProtectionProgramMember_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Paycheck protection program.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_PaycheckProtectionProgramMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Paycheck Protection Program [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_PaycheckProtectionProgramMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Paycheck Protection Program [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FinancingReceivableRecordedInvestmentLineItems_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Financing Receivable, Credit Quality Indicator [Line Items]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FinancingReceivableRecordedInvestmentLineItems_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Financing Receivable Recorded Investment [Line Items]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_IncreaseDecreaseInOtherOperatingLiabilities_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Increase (Decrease) in Other Operating Liabilities</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_IncreaseDecreaseInOtherOperatingLiabilities_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Increase (Decrease) in Other Operating Liabilities, Total</link:label>
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          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AvailableForSaleDebtSecuritiesAmortizedCostBasis_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Debt Securities, Available-for-Sale, Amortized Cost</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AvailableForSaleDebtSecuritiesAmortizedCostBasis_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Available-for-sale, amortized cost</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AvailableForSaleDebtSecuritiesAmortizedCostBasis_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Available-for-sale, amortized cost</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_HeldToMaturitySecuritiesContinuousUnrealizedLossPositionLessThan12MonthsAccumulatedLoss_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Debt Securities, Held-to-Maturity, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_HeldToMaturitySecuritiesContinuousUnrealizedLossPositionLessThan12MonthsAccumulatedLoss_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Debt securities held to maturities in unrealized loss position</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_HeldToMaturitySecuritiesContinuousUnrealizedLossPositionLessThan12MonthsAccumulatedLoss_lbl" xlink:role="http://www.xbrl.org/2009/role/negatedLabel">Held-to-maturity, less than 12 months, unrealized losses</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AvailableForSaleSecuritiesDebtSecurities_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Available-for-sale, amortized cost</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AvailableForSaleSecuritiesDebtSecurities_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Investment securities available-for-sale, at fair value (amortized cost $174,597 and $144,893; net of allowance for credit losses of $- and $-)</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AvailableForSaleSecuritiesDebtSecurities_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Investment securities available-for-sale, at fair value (amortized cost $169,037 and $174,597; net of allowance for credit losses of $- and $-)</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AvailableForSaleSecuritiesDebtSecurities_lbl" xlink:role="http://www.xbrl.org/2003/role/verboseLabel">Investment securities available-for-sale, at fair value</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_NoninterestIncomeAbstract_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Noninterest Income [Abstract]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_NoninterestIncomeAbstract_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Non-interest income:</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_NoninterestIncomeAbstract_lbl" xlink:role="http://www.xbrl.org/2003/role/verboseLabel">Non-interest:</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="dei_DocumentFinStmtErrorCorrectionFlag_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Document Financial Statement Error Correction [Flag]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_OtherRestructuringCosts_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Other Restructuring Costs</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_OtherRestructuringCosts_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Other expenses</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_StockIssuedDuringPeriodSharesStockOptionsExercised_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Exercises in Period</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_StockIssuedDuringPeriodSharesStockOptionsExercised_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Exercised (in shares)</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_IncreaseDecreaseInFederalFundsSoldAndSecuritiesPurchasedUnderReverseRepurchaseAgreements_lbl" xlink:role="http://www.xbrl.org/2003/role/label">(Increase) Decrease in Federal Funds Sold and Securities Purchased under Reverse Repurchase Agreements</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_IncreaseDecreaseInFederalFundsSoldAndSecuritiesPurchasedUnderReverseRepurchaseAgreements_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">(Increase) decrease in federal funds sold and securities purchased under reverse repurchase agreements.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_IncreaseDecreaseInFederalFundsSoldAndSecuritiesPurchasedUnderReverseRepurchaseAgreements_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Net decrease in federal funds sold and securities purchased under reverse repurchase agreements</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DoubtfulMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Doubtful [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DoubtfulMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Doubtful [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DebtDisclosureAbstract_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Debt Disclosure [Abstract]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_OtherMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Other [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_OtherMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Other [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_OtherMember_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Other [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_CreditLossesOnUnfundedLendingCommitmentsMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Credit Losses On Unfunded Lending Commitments [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_CreditLossesOnUnfundedLendingCommitmentsMember_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Credit losses on unfunded lending commitments.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_CreditLossesOnUnfundedLendingCommitmentsMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Credit Losses on Unfunded Lending Commitments [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DerivativeTable_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Derivative [Table]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DerivativeTable_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Derivative [Table]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_DeferredTaxLiabilitiesPartnerships_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Deferred tax liabilities partnerships</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_DeferredTaxLiabilitiesPartnerships_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Deferred Tax Liabilities Partnerships</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_DeferredTaxLiabilitiesPartnerships_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Limited partnerships</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_EstimateOfFairValueFairValueDisclosureMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Estimate of Fair Value Measurement [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_EstimateOfFairValueFairValueDisclosureMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Estimate of Fair Value Measurement [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FinancialInstrumentsFinancialAssetsBalanceSheetGroupingsAbstract_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Financial Instruments, Financial Assets, Balance Sheet Groupings [Abstract]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FinancialInstrumentsFinancialAssetsBalanceSheetGroupingsAbstract_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Assets:</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DerivativeNotionalAmount_lbl" xlink:role="http://www.xbrl.org/2003/role/verboseLabel">Notional amount</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DerivativeNotionalAmount_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Derivative, Notional Amount</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DerivativeNotionalAmount_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Notional Amount</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FinancialInstrumentPerformanceStatusDomain_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Financial Instrument Performance Status [Domain]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FinancialInstrumentPerformanceStatusDomain_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Financial Instrument Performance Status</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="dei_CurrentFiscalYearEndDate_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Current Fiscal Year End Date</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="dei_CurrentFiscalYearEndDate_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Current Fiscal Year End Date</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DebtInstrumentTable_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Schedule of Long-Term Debt Instruments [Table]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DebtInstrumentTable_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Debt Instrument [Table]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_InterestRateSwapsRelatedToFHLBAdvancesMember_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Interest rate swaps related to FHLB advances.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_InterestRateSwapsRelatedToFHLBAdvancesMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Interest Rate Swaps Related To F H L B Advances [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_InterestRateSwapsRelatedToFHLBAdvancesMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Interest Rate Swaps Related to FHLB Advances [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_InvestmentsInAffiliatesSubsidiariesAssociatesAndJointVentures_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Investments in and Advance to Affiliates, Subsidiaries, Associates, and Joint Ventures</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_InvestmentsInAffiliatesSubsidiariesAssociatesAndJointVentures_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Investment in subsidiaries</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_InvestmentsInAffiliatesSubsidiariesAssociatesAndJointVentures_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Investments in and Advance to Affiliates, Subsidiaries, Associates, and Joint Ventures, Total</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_InterestRateSwapThreeMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Interest Rate Swap Three [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_InterestRateSwapThreeMember_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Interest rate swap three.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_OtherCostAndExpenseOperating_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Other Cost and Expense, Operating</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_OtherCostAndExpenseOperating_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Other expense</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_HedgeTerminatedInTwoThousandTwentyTwoMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Hedge Terminated in Two Thousand Twenty Two [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_HedgeTerminatedInTwoThousandTwentyTwoMember_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Hedge Terminated in 2022.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_HedgeTerminatedInTwoThousandTwentyTwoMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Hedge Terminated In 2022 [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_OtherAssetsInterestRateCapMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Other Assets Interest Rate Cap [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_OtherAssetsInterestRateCapMember_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Other assets interest rate cap.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ReceivablesAbstract_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Receivables [Abstract]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AdvertisingCostsPolicyTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Advertising Cost [Policy Text Block]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AdvertisingCostsPolicyTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Advertising Cost</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="dei_EntityAddressStateOrProvince_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Entity Address, State or Province</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="dei_EntityAddressStateOrProvince_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Entity Address, State or Province</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Nonvested, Number</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber_lbl" xlink:role="http://www.xbrl.org/2003/role/periodStartLabel">Nonvested shares, beginning of year (in shares)</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber_lbl" xlink:role="http://www.xbrl.org/2003/role/periodEndLabel">Nonvested shares, end of year (in shares)</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ProceedsFromRepaymentsOfShortTermDebt_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Proceeds from (Repayments of) Short-Term Debt</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ProceedsFromRepaymentsOfShortTermDebt_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Proceeds from (Repayments of) Short-Term Debt, Total</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ProceedsFromRepaymentsOfShortTermDebt_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Net decrease in short-term borrowings</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FinancialInstrumentPerformanceStatusAxis_lbl" xlink:role="http://www.xbrl.org/2003/role/verboseLabel">Financial Instrument Performance Status</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FinancialInstrumentPerformanceStatusAxis_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Financial Instrument Performance Status [Axis]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FinancialInstrumentPerformanceStatusAxis_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Performing Financial Instruments</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_CustomerRelatedInterestRateSwapsBorrowerMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Customer Related Interest Rate Swaps Borrower [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_CustomerRelatedInterestRateSwapsBorrowerMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Customer related interest rate swaps borrower [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_CustomerRelatedInterestRateSwapsBorrowerMember_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Customer related interest rate swaps borrower.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedGainBeforeTax_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Debt Securities, Available-for-Sale, Accumulated Gross Unrealized Gain, before Tax</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedGainBeforeTax_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Available-for-sale, gross unrealized gains</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_IncreaseDecreaseInAccruedInterestReceivableNet_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Increase (Decrease) in Accrued Interest Receivable, Net</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_IncreaseDecreaseInAccruedInterestReceivableNet_lbl" xlink:role="http://www.xbrl.org/2009/role/negatedLabel">(Increase) decrease in accrued interest receivable</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_InternalCreditAssessmentAxis_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Internal Credit Assessment</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_InternalCreditAssessmentAxis_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Internal Credit Assessment [Axis]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FinancingReceivableAccruedInterestAfterAllowanceForCreditLoss_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Financing Receivable, Accrued Interest, after Allowance for Credit Loss</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FinancingReceivableAccruedInterestAfterAllowanceForCreditLoss_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Accrued interest receivable</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_IncomeTaxReconciliationStateAndLocalIncomeTaxes_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Effective Income Tax Rate Reconciliation, State and Local Income Taxes, Amount</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_IncomeTaxReconciliationStateAndLocalIncomeTaxes_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">State and local income taxes, net of federal income tax effect</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ProfessionalFees_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Professional Fees</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ProfessionalFees_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Fees for professional services</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_IndirectConsumersMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Indirect Consumers [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_IndirectConsumersMember_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Indirect consumers.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_IndirectConsumersMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Indirect Consumer [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ComprehensiveIncomePolicyPolicyTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Comprehensive Income, Policy [Policy Text Block]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ComprehensiveIncomePolicyPolicyTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Comprehensive Income</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ScheduleOfDeferredTaxAssetsAndLiabilitiesTableTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Schedule of Deferred Tax Assets and Liabilities [Table Text Block]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ScheduleOfDeferredTaxAssetsAndLiabilitiesTableTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Schedule of Deferred Tax Assets and Liabilities</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_OtherComprehensiveIncomeLossNetOfTaxPeriodIncreaseDecreaseAbstract_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Other Comprehensive Income (Loss), Net of Tax [Abstract]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_OtherComprehensiveIncomeLossNetOfTaxPeriodIncreaseDecreaseAbstract_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Other comprehensive income:</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LongTermDebtFairValue_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Long-Term Debt, Fair Value</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LongTermDebtFairValue_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Long-term borrowings</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_SubsequentEventMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Subsequent Event [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_HeldToMaturitySecuritiesContinuousUnrealizedLossPosition12MonthsOrLongerAccumulatedLoss_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Debt Securities, Held-to-Maturity, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_HeldToMaturitySecuritiesContinuousUnrealizedLossPosition12MonthsOrLongerAccumulatedLoss_lbl" xlink:role="http://www.xbrl.org/2009/role/negatedLabel">Held-to-maturity, 12 months or more, unrealized losses</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_MarketableSecuritiesPolicy_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Marketable Securities, Policy [Policy Text Block]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_MarketableSecuritiesPolicy_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Investment Securities</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_PropertyPlantAndEquipmentAbstract_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Property, Plant and Equipment [Abstract]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_InterestIncomeExpenseAfterProvisionForLoanLoss_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Net interest income after provision for credit losses</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_InterestIncomeExpenseAfterProvisionForLoanLoss_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Interest Income (Expense), after Provision for Loan Loss</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_TypeOfRevenueExtensibleList_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Revenue, Product and Service [Extensible Enumeration]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FairValueAssetsMeasuredOnNonrecurringBasisValuationTechniquesTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Fair Value, Assets and Liabilities Measured on Nonrecurring Basis, Valuation Techniques [Table Text Block]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FairValueAssetsMeasuredOnNonrecurringBasisValuationTechniquesTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Fair Value, Assets and Liabilities Measured on Nonrecurring Basis, Valuation Techniques</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_SecuredByRealEstate1To4FamilyResidentialPropertiesMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Secured by Real Estate 1-4 Family Residential Properties [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_SecuredByRealEstate1To4FamilyResidentialPropertiesMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Secured By Real Estate 1 To 4 Family Residential Properties Member</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_SecuredByRealEstate1To4FamilyResidentialPropertiesMember_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Represents information pertaining to loans secured by real estate 1-to-4-family residential properties.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExpirationsInPeriod_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Expirations in Period</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExpirationsInPeriod_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Expired (in shares)</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_EmployeesMember_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Employees.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_EmployeesMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Employees [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_EmployeesMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Employees [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_GoodwillAndIntangibleAssetsIntangibleAssetsPolicy_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Goodwill and Intangible Assets, Intangible Assets, Policy [Policy Text Block]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_GoodwillAndIntangibleAssetsIntangibleAssetsPolicy_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Goodwill and Other Intangible Assets</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_CommonEquityTierOneCapitalRatio_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Banking Regulation, Common Equity Tier 1 Risk-Based Capital Ratio, Actual</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_CommonEquityTierOneCapitalRatio_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Common equity Tier 1 capital (to risk-weighted assets), Actual Regulatory Capital, Ratio</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_StateAndLocalJurisdictionMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">State and Local Jurisdiction [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_StateAndLocalJurisdictionMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">State [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_CorrespondentBanksMember_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Correspondent Banks [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_CorrespondentBanksMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Correspondent Banks [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_CorrespondentBanksMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Correspondent Banks [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AccumulatedOtherComprehensiveIncomeMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">AOCI Attributable to Parent [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AccumulatedOtherComprehensiveIncomeMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Accumulated Other Comprehensive Loss [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DerivativeLiabilities_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Derivative Liability</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DerivativeLiabilities_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Other liabilities - derivatives</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DerivativeLiabilities_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Derivative Liability, Total</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DerivativeLiabilities_lbl" xlink:role="http://www.xbrl.org/2003/role/verboseLabel">Other liabilities - interest rate swaps</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Finite-Lived Intangible Assets, Major Class Name [Domain]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Finite-Lived Intangible Assets, Major Class Name</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_TreasuryStockCommonShares_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Treasury Stock, shares</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_TreasuryStockCommonShares_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Treasury Stock, Common, Shares</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_AcceptanceLoanCompanyMember_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Represents a segment of the company.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_AcceptanceLoanCompanyMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Acceptance Loan Company [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_AcceptanceLoanCompanyMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">ALC [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_StockIssuedDuringPeriodSharesTreasuryStockReissued_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Stock Issued During Period, Shares, Treasury Stock Reissued</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_StockIssuedDuringPeriodSharesTreasuryStockReissued_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Reissuance of treasury stock as compensation (in shares)</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_InterestRateSwapTwoMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Interest Rate Swap Two [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_InterestRateSwapTwoMember_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Interest rate swap two.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_InterestRateDerivativeAssetsAtFairValue_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Interest Rate Derivative Assets, at Fair Value</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_InterestRateDerivativeAssetsAtFairValue_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Derivative contracts, assets at fair value</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_InterestRateDerivativeAssetsAtFairValue_lbl" xlink:role="http://www.xbrl.org/2003/role/verboseLabel">Interest rate derivative contracts, assets at fair value</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_OtherLiabilitiesCustomerRelatedInterestRateSwapsThirdPartyCounterpartiesMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Other Liabilities Customer Related Interest Rate Swaps Third Party Counterparties [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_OtherLiabilitiesCustomerRelatedInterestRateSwapsThirdPartyCounterpartiesMember_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Other liabilities customer related interest rate swaps third party counterparties.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_InterestRateFloorsMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Interest Rate Floors [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_InterestRateFloorsMember_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Interest rate floors.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_InterestRateFloorsMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Interest Rate Floors [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DebtInstrumentMaturityDate_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Debt Instrument, Maturity Date</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DebtInstrumentMaturityDate_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Maturity date</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="srt_MinimumMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Minimum [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="srt_MinimumMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Minimum [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Granted, weighted-average grant-date fair value (in dollars per share)</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FinancialInstrumentAxis_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Financial Instrument [Axis]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FinancialInstrumentAxis_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Financial Instrument</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_ForwardInterestRateSwapContractsOneMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Forward Interest Rate Swap Contracts One [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_ForwardInterestRateSwapContractsOneMember_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Forward interest rate swap contracts one.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_ForwardInterestRateSwapContractsOneMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Forward Interest Rate Swap Contracts One [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FinancingReceivableOriginatedInFiscalYearBeforeLatestFiscalYear_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Financing Receivable, Year Two, Originated, Fiscal Year before Current Fiscal Year</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FinancingReceivableOriginatedInFiscalYearBeforeLatestFiscalYear_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">2024</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_RealEstateMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Real Estate [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_RealEstateMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Real Estate [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_QuarterlyFinancialInformationTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Quarterly Financial Information [Text Block]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_QuarterlyFinancialInformationTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Quarterly Financial Information</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_SecuredBy1To4FamilyResidentialPropertiesMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Secured by 1-4 Family Residential Properties [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_SecuredBy1To4FamilyResidentialPropertiesMember_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Represents information pertaining to loans secured by 1-to-4-family residential properties.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_SecuredBy1To4FamilyResidentialPropertiesMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Secured By1 To4 Family Residential Properties [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AmortizationOfIntangibleAssets_lbl" xlink:role="http://www.xbrl.org/2003/role/verboseLabel">Software amortization</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AmortizationOfIntangibleAssets_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Amortization of Intangible Assets</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AmortizationOfIntangibleAssets_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Amortization of intangible assets</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DeferredTaxAssetsUnrealizedLossesOnAvailableforSaleSecuritiesGross_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Deferred Tax Asset, Debt Securities, Available-for-Sale, Unrealized Loss</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DeferredTaxAssetsUnrealizedLossesOnAvailableforSaleSecuritiesGross_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Unrealized loss on securities available-for-sale</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FairValueInputsLevel3Member_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Fair Value, Inputs, Level 3 [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FairValueInputsLevel3Member_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Fair Value, Inputs, Level 3 [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FairValueMeasurementsNonrecurringMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Fair Value, Nonrecurring [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FairValueMeasurementsNonrecurringMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Fair Value, Nonrecurring [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_SegmentReportingAbstract_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Segment Reporting [Abstract]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DeferredTaxLiabilitiesPropertyPlantAndEquipment_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Deferred Tax Liabilities, Property, Plant and Equipment</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DeferredTaxLiabilitiesPropertyPlantAndEquipment_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Premises and equipment</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FairValueAssetsMeasuredOnRecurringBasisTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Fair Value, Assets Measured on Recurring Basis [Table Text Block]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FairValueAssetsMeasuredOnRecurringBasisTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Fair Value, Assets Measured on Recurring Basis</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_TimeDepositMaturitiesYearFour_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Time Deposit Maturities, Year Four</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_TimeDepositMaturitiesYearFour_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">2028</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_CollateralDependentLoansFairValueDisclosure_lbl" xlink:role="http://www.xbrl.org/2003/role/verboseLabel">Collateral dependent loans</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_CollateralDependentLoansFairValueDisclosure_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Collateral dependent loans</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_CollateralDependentLoansFairValueDisclosure_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Collateral Dependent Loans Fair Value disclosure</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_CollateralDependentLoansFairValueDisclosure_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Collateral dependent loans fair value disclosure.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_RestructuringAndRelatedActivitiesDisclosureTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Restructuring and Related Activities Disclosure [Text Block]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_RestructuringAndRelatedActivitiesDisclosureTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Restructuring Charges</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_StockRepurchasedAndRetiredDuringPeriodValue_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Stock Repurchased and Retired During Period, Value</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_StockRepurchasedAndRetiredDuringPeriodValue_lbl" xlink:role="http://www.xbrl.org/2009/role/negatedLabel">Impact of common stock share repurchases</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FinancingReceivableNonaccrualTable_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Financing Receivable, Nonaccrual [Table]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_MinimumCommitmentRequiredForEvaluatingIdividually_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Minimum commitment required for evaluating idividually</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_MinimumCommitmentRequiredForEvaluatingIdividually_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Minimum Commitment Required for Evaluating Idividually</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_MinimumCommitmentRequiredForEvaluatingIdividually_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Minimum commitment required for evaluating idividually.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_SharesOutstanding_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Shares, Outstanding</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_SharesOutstanding_lbl" xlink:role="http://www.xbrl.org/2003/role/periodEndLabel">Balance (in shares)</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_SharesOutstanding_lbl" xlink:role="http://www.xbrl.org/2003/role/periodStartLabel">Balance (in shares)</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_OperatingLossCarryforwards_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Operating Loss Carryforwards</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_OperatingLossCarryforwards_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Net operating loss carryforwards</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_OtherLiabilitiesCreditRiskParticipationAgreement_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Other Liabilities - Credit Risk Participation Agreement</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_OtherLiabilitiesCreditRiskParticipationAgreement_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Other liabilities - credit risk participation agreement.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_OtherLiabilitiesCreditRiskParticipationAgreement_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Other liabilities - credit risk participation agreement</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ScheduleOfAccountsNotesLoansAndFinancingReceivableTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Schedule of Accounts, Notes, Loans and Financing Receivable [Table Text Block]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ScheduleOfAccountsNotesLoansAndFinancingReceivableTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Schedule of Loan Portfolio</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_InterestExpenseAbstract_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Interest Expense, Operating and Nonoperating [Abstract]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_InterestExpenseAbstract_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Interest expense:</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_InterestExpenseAbstract_lbl" xlink:role="http://www.xbrl.org/2003/role/verboseLabel">Less:</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_OtherIncome_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Other Income</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_OtherIncome_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Other income</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LesseeOperatingLeaseRenewalTerm_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Lessee, Operating Lease, Renewal Term</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LesseeOperatingLeaseRenewalTerm_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Lessee, Operating Lease, Renewal Term</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DeferredTaxAssetsTaxDeferredExpenseCompensationAndBenefits_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Deferred Tax Assets, Tax Deferred Expense, Compensation and Benefits</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DeferredTaxAssetsTaxDeferredExpenseCompensationAndBenefits_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Deferred compensation</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DeferredTaxAssetsTaxDeferredExpenseCompensationAndBenefits_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Deferred Tax Assets, Tax Deferred Expense, Compensation and Benefits, Total</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue_lbl" xlink:role="http://www.xbrl.org/2003/role/periodStartLabel">Nonvested shares, beginning of year, weighted-average grant-date fair value (in dollars per share)</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue_lbl" xlink:role="http://www.xbrl.org/2003/role/periodEndLabel">Nonvested shares, end of year, weighted-average grant-date fair value (in dollars per share)</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_StockIssuedDuringPeriodSharesShareBasedCompensation_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Shares Issued, Shares, Share-Based Payment Arrangement, after Forfeiture</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_StockIssuedDuringPeriodSharesShareBasedCompensation_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Impact of stock-based compensation plans, net (in shares)</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_StockIssuedDuringPeriodSharesShareBasedCompensation_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Shares Issued, Shares, Share-Based Payment Arrangement, after Forfeiture, Total</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_OperatingLeaseLiability_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Operating Lease, Liability</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_OperatingLeaseLiability_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Operating lease liabilities</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_OperatingLeaseLiability_lbl" xlink:role="http://www.xbrl.org/2003/role/verboseLabel">Total</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_OperatingLeaseLiability_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Operating Lease, Liability, Total</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_ImpairedLoansFairValue_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Fair value portion of impaired loans by an entity as a result of past transactions or events.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_ImpairedLoansFairValue_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Impaired Loans Fair Value</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_ImpairedLoansFairValue_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Impaired loans</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LoansAndLeasesReceivableGrossCarryingAmount_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Loans and leases held for investment</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LoansAndLeasesReceivableGrossCarryingAmount_lbl" xlink:role="http://www.xbrl.org/2003/role/verboseLabel">Total</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LoansAndLeasesReceivableGrossCarryingAmount_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Loans</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_RemainingUnrealizedGainsAssociatedWithTerminatedDerivatives_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Remaining Unrealized Gains Associated With Terminated Derivatives</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_RemainingUnrealizedGainsAssociatedWithTerminatedDerivatives_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Remaining unrealized gains associated with terminated derivatives.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_RemainingUnrealizedGainsAssociatedWithTerminatedDerivatives_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Remaining unrealized gains associated with terminated derivatives</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="dei_AuditorFirmId_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Auditor Firm ID</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="dei_AuditorFirmId_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Auditor Firm ID</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FinancingReceivableCollectivelyEvaluatedForImpairment_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Financing Receivable, Collectively Evaluated for Credit Loss</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FinancingReceivableCollectivelyEvaluatedForImpairment_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Collectively evaluated for impairment</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DebtInstrumentBasisSpreadOnVariableRate1_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Debt Instrument, Basis Spread on Variable Rate</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DebtInstrumentBasisSpreadOnVariableRate1_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Variable interest rate</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="srt_ScenarioForecastMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Forecast [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="srt_ScenarioForecastMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Scenario Forecast [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ShortTermBorrowings_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Short-Term Debt</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ShortTermBorrowings_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Short-term borrowings</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ShortTermBorrowings_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Short-Term Debt, Total</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_CreditLossStatusAxis_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Credit Loss Status [Axis]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_CreditLossStatusAxis_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Credit Loss Status</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_InterestRateCapTwoMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Interest Rate Cap Two [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_InterestRateCapTwoMember_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Interest rate cap two.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_StockIssuedDuringPeriodValueTreasuryStockReissued_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Stock Issued During Period, Value, Treasury Stock Reissued</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_StockIssuedDuringPeriodValueTreasuryStockReissued_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Reissuance of treasury stock as compensation</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DebtSecuritiesAvailableForSaleRestricted_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Debt Securities, Available-for-Sale, Restricted</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DebtSecuritiesAvailableForSaleRestricted_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Debt Securities, Available-for-sale, Restricted</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_HedgedAssetFairValueHedgeCumulativeIncreaseDecrease_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Hedged Asset, Fair Value Hedge, Cumulative Increase (Decrease)</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_HedgedAssetFairValueHedgeCumulativeIncreaseDecrease_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Cumulative Amount of Fair Value Hedging Adjustment Included in the Carrying Amount of the Hedged Assets</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DerivativeCashReceivedOnHedge_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Derivative, cash received on hedge</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DerivativeCashReceivedOnHedge_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Derivative, Cash Received on Hedge</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_MaturityPeriodOfFederalFunds_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Maturity Period Of Federal Funds</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_MaturityPeriodOfFederalFunds_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Maturity period of federal funds.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_MaturityPeriodOfFederalFunds_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Maturity Period of Federal Funds</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LesseeLeaseDescriptionTable_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Lessee, Lease, Description [Table]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LesseeLeaseDescriptionTable_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Lessee Lease Description [Table]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_InterestAndDividendIncomeOperating_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Interest and Dividend Income, Operating</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_InterestAndDividendIncomeOperating_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Total interest income</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_InterestAndDividendIncomeOperating_lbl" xlink:role="http://www.xbrl.org/2003/role/verboseLabel">Interest income</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_InterestAndDividendIncomeOperating_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Total interest income</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FinancingReceivableOriginatedFiveOrMoreYearsBeforeLatestFiscalYear_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Prior</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FinancingReceivableOriginatedFiveOrMoreYearsBeforeLatestFiscalYear_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Financing Receivable, Originated, More than Five Years before Current Fiscal Year</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_InterestIncomeExpenseNet_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Interest Income (Expense), Operating</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_InterestIncomeExpenseNet_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Net interest income</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ProfitLoss_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Net Income (Loss), Including Portion Attributable to Noncontrolling Interest</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ProfitLoss_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Net income</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ProfitLoss_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Net income (loss)</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_NotesReceivableGross_lbl" xlink:role="http://www.xbrl.org/2003/role/verboseLabel">Nonaccrual loans with no allowance for credit losses</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_NotesReceivableGross_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Financing Receivable, before Allowance for Credit Loss</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_NotesReceivableGross_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Loans</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_NotesReceivableGross_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Financing Receivable, before Allowance for Credit Loss, Total</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_HeldToMaturitySecurities_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Debt Securities, Held-to-Maturity, Amortized Cost, before Allowance for Credit Loss</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_HeldToMaturitySecurities_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Investment securities held-to-maturity, at amortized cost</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_HeldToMaturitySecurities_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Held-to-maturity, amortized cost</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_HeldToMaturitySecurities_lbl" xlink:role="http://www.xbrl.org/2003/role/verboseLabel">Investment securities held-to-maturity, at amortized cost, net of allowance for credit losses of $- and $-, (fair value 2025 - $449, 2024 - $642)</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FinancingReceivableRecordedInvestment90DaysPastDueAndStillAccruing_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Accruing loans past due 90 days or more amounted</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FinancingReceivableRecordedInvestment90DaysPastDueAndStillAccruing_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Financing Receivable, 90 Days or More Past Due, Still Accruing</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_RealEstatePolicyTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Real Estate, Policy [Policy Text Block]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_RealEstatePolicyTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Other Real Estate Owned (OREO)</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LongtermDebtTypeDomain_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Long-Term Debt, Type [Domain]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LongtermDebtTypeDomain_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Long-term Debt, Type</link:label>
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          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LossContingenciesTable_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Loss Contingencies [Table]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_WeightedAverageNumberOfSharesOutstandingBasic_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Weighted Average Number of Shares Outstanding, Basic</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_WeightedAverageNumberOfSharesOutstandingBasic_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Basic shares</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_WeightedAverageNumberOfSharesOutstandingBasic_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Weighted Average Number of Shares Outstanding, Basic, Total</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_CreditDerivativesMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Credit Derivatives [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_CreditDerivativesMember_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Credit derivatives.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AllowanceForLoanAndLeaseLossesWriteOffs_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Current period gross charge-offs</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AllowanceForLoanAndLeaseLossesWriteOffs_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Allowance for Loan and Lease Losses, Writeoff</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="srt_StatementScenarioAxis_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Scenario [Axis]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="srt_StatementScenarioAxis_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Scenario</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_ProceedsFromSettlementOfDerivativeContracts_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Proceeds from settlement of derivative contracts</link:label>
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          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_IncomeTaxReconciliationOtherReconcilingItems_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Other reconciling items</link:label>
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          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_AllowanceForLoanAndLeaseLossesWriteOffsFourYearsBeforeLatestFiscalYear_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Allowance for loan and lease losses write offs four years before latest fiscal year.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_AllowanceForLoanAndLeaseLossesWriteOffsFourYearsBeforeLatestFiscalYear_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Current period gross charge-offs, 2021</link:label>
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          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Schedule of Share-Based Compensation Arrangements by Share-Based Payment Award [Table]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Schedule Of Share Based Compensation Arrangements By Share Based Payment Award [Table]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPosition12MonthsOrLongerAccumulatedLoss_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Debt Securities, Available-for-Sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPosition12MonthsOrLongerAccumulatedLoss_lbl" xlink:role="http://www.xbrl.org/2009/role/negatedLabel">Available-for-sale, 12 months or more, unrealized losses</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_StatementBusinessSegmentsAxis_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Segments [Axis]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_StatementBusinessSegmentsAxis_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Segments</link:label>
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          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_OtherComprehensiveIncomeLossDerivativeExcludedComponentIncreaseDecreaseAfterAdjustmentsTaxNoncontrollingInterest1_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Other Comprehensive Income (Loss), Derivative, Excluded Component, Increase (Decrease), after Adjustments, Tax, Noncontrolling Interest</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_OtherComprehensiveIncomeLossDerivativeExcludedComponentIncreaseDecreaseAfterAdjustmentsTaxNoncontrollingInterest1_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Net change in fair value of derivative instruments, net of tax</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="cyd_CybersecurityRiskProcessForInformingManagementOrCommitteesResponsibleTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Cybersecurity Risk Process for Informing Management or Committees Responsible [Text Block]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AssetPledgedAsCollateralMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Asset Pledged as Collateral [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AssetPledgedAsCollateralMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Pledged as Collateral [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DeferredCompensationLiabilityCurrentAndNoncurrent_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Deferred Compensation Liability, Current and Noncurrent</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DeferredCompensationLiabilityCurrentAndNoncurrent_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Deferred Compensation Liability, Current and Noncurrent, Total</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DeferredCompensationLiabilityCurrentAndNoncurrent_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Deferred Compensation Liability, Current and Noncurrent, Total</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LoansReceivableFairValueDisclosure_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Loans, net of allowance for credit losses</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LoansReceivableFairValueDisclosure_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Loans Receivable, Fair Value Disclosure</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_OtherComprehensiveIncomeLossCashFlowHedgeGainLossAfterReclassificationTax_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), after Reclassification, Tax, Total</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_OtherComprehensiveIncomeLossCashFlowHedgeGainLossAfterReclassificationTax_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), after Reclassification, Tax</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_OtherComprehensiveIncomeLossCashFlowHedgeGainLossAfterReclassificationTax_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Reclassification adjustments on cash flow hedge derivatives realized in net income, tax benefit</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LongTermDebt_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Long-Term Debt</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LongTermDebt_lbl" xlink:role="http://www.xbrl.org/2003/role/periodEndLabel">Ending balance</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LongTermDebt_lbl" xlink:role="http://www.xbrl.org/2003/role/periodStartLabel">Beginning balance</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LongTermDebt_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Long-term borrowings</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LongTermDebt_lbl" xlink:role="http://www.xbrl.org/2003/role/verboseLabel">Loan, aggregate principal balance</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LongTermDebt_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Long-Term Debt, Total</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_TierOneRiskBasedCapitalToRiskWeightedAssets_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Banking Regulation, Tier 1 Risk-Based Capital Ratio, Actual</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_TierOneRiskBasedCapitalToRiskWeightedAssets_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Tier 1 capital (to risk-weighted assets), Actual Regulatory Capital, Ratio</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_SecuritiesSoldUnderAgreementsToRepurchase_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Securities Sold under Agreements to Repurchase</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_SecuritiesSoldUnderAgreementsToRepurchase_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Securities Sold under Agreements to Repurchase, Total</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_SecuritiesSoldUnderAgreementsToRepurchase_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Securities Sold under Agreements to Repurchase, Total</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DebtInstrumentInterestRateTerms_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Debt Instrument, Interest Rate Terms</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DebtInstrumentInterestRateTerms_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Interest rate, description</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_VariableRateDomain_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Variable Rate [Domain]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_EquityInUndistributedEarningsOfSubsidiary_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Equity in undistributed earnings of subsidiary.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_EquityInUndistributedEarningsOfSubsidiary_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Equity In Undistributed Earnings Of Subsidiary</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_EquityInUndistributedEarningsOfSubsidiary_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Equity in undistributed income of subsidiaries</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIForSaleOfSecuritiesTax_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Reclassification adjustment for net losses on securities available-for-sale realized in net income, tax expense</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIForSaleOfSecuritiesTax_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI for Sale of Securities, Tax</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_IncomeTaxDisclosureLineItems_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Income Tax Disclosure [Line Items]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_IncomeTaxDisclosureLineItems_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Income tax disclosure.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_StatementOfStockholdersEquityAbstract_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Statement of Stockholders' Equity [Abstract]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_CorporateNoteSecuritiesMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Corporate Notes [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_CorporateNoteSecuritiesMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Corporate Note Securities [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_InterestRateFloorContractsOneMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Interest Rate Floor Contracts One [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_InterestRateFloorContractsOneMember_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Interest rate floor contracts one.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_InterestRateFloorContractsOneMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Interest Rate Floor Contracts One [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_HeldToMaturitySecuritiesAccumulatedUnrecognizedHoldingLoss_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Debt Securities, Held-to-Maturity, Accumulated Unrecognized Loss</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_HeldToMaturitySecuritiesAccumulatedUnrecognizedHoldingLoss_lbl" xlink:role="http://www.xbrl.org/2009/role/negatedLabel">Held-to-maturity, gross unrealized losses</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_TypeOfRestructuringDomain_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Type of Restructuring [Domain]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_TypeOfRestructuringDomain_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Type of Restructuring</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_UseOfEstimates_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Use of Estimates, Policy [Policy Text Block]</link:label>
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          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_InternalCreditAssessmentDomain_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Internal Credit Assessment [Domain]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_InternalCreditAssessmentDomain_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Internal Credit Assessment</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_TreasuryStockCommonMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Treasury Stock [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_TreasuryStockCommonMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Treasury Stock, Common [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FinancingReceivableAllowanceForCreditLosses_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Financing Receivable, Allowance for Credit Loss</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FinancingReceivableAllowanceForCreditLosses_lbl" xlink:role="http://www.xbrl.org/2003/role/periodEndLabel">Financing Receivable, Allowance for Credit Loss, Ending Balance</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FinancingReceivableAllowanceForCreditLosses_lbl" xlink:role="http://www.xbrl.org/2003/role/periodStartLabel">Financing Receivable, Allowance for Credit Loss, Beginning Balance</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FinancingReceivableAllowanceForCreditLosses_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Allowance for credit loss</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="srt_ScheduleOfCondensedIncomeStatementTableTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Condensed Income Statement [Table Text Block]</link:label>
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          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_ScheduleOfLoanAndLeaseLossesAndRecordedInvestmentInLoansByLoanClassificationAndByImpairmentEvaluationTableTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Schedule of Loan and Lease Losses and Recorded Investment in Loans by Loan Classification and by Impairment Evaluation [Table Text Block]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_ScheduleOfLoanAndLeaseLossesAndRecordedInvestmentInLoansByLoanClassificationAndByImpairmentEvaluationTableTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Schedule of loan and lease losses and recorded investment in loans by loan classification and by impairment evaluation table text block.</link:label>
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          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_AllowanceForCreditLossesPolicyPolicyTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Allowance for Credit Losses Policy [Policy Text Block]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_AllowanceForCreditLossesPolicyPolicyTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Allowance for credit losses policy.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_TransitionAdjustmentIncreaseInLoanLossReserves_lbl" xlink:role="http://www.xbrl.org/2003/role/verboseLabel">Decrease to retained earnings</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_TransitionAdjustmentIncreaseInLoanLossReserves_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Transition adjustment increase in allowance for credit losses</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_TransitionAdjustmentIncreaseInLoanLossReserves_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Transition adjustment increase in loan loss reserves.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_TransitionAdjustmentIncreaseInLoanLossReserves_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Transition adjustment increase in loan loss reserves</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingRollForward_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Outstanding [Roll Forward]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingRollForward_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DerivativeInstrumentsAndHedgingActivitiesDisclosureAbstract_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Derivative Instruments and Hedging Activities Disclosure [Abstract]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_SegmentReportingCodmIndividualTitleAndPositionOrGroupOrCommitteeNameExtensibleEnumeration_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Segment Reporting, CODM, Individual Title and Position or Group Name [Extensible Enumeration]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_OtherIncomeAndExpensesTable_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Other Income and Expenses [Table]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_OtherIncomeAndExpensesTable_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Other income and expenses table.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_CondensedFinancialInformationOfParentCompanyOnlyDisclosureTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Condensed Financial Information of Parent Company Only Disclosure [Text Block]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_CondensedFinancialInformationOfParentCompanyOnlyDisclosureTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Condensed Financial Information of Parent Company Only Disclosure</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_SegmentReportingOtherItemAmount_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Segment Reporting, Other Segment Item, Amount</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_SegmentReportingOtherItemAmount_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Other segment items</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_PlanNameDomain_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Plan Name</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_PlanNameDomain_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Plan Name [Domain]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_IncreaseDecreaseInOtherOperatingAssets_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Increase (Decrease) in Other Operating Assets</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_IncreaseDecreaseInOtherOperatingAssets_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Increase (Decrease) in Other Operating Assets, Total</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_IncreaseDecreaseInOtherOperatingAssets_lbl" xlink:role="http://www.xbrl.org/2009/role/negatedLabel">Increase in other assets</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_InterestExpense_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Interest Expense, Operating and Nonoperating</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_InterestExpense_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Total interest expense</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_InterestExpense_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Total interest expense</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_InterestExpense_lbl" xlink:role="http://www.xbrl.org/2003/role/verboseLabel">Interest expense</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="dei_EntityDomain_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Entity [Domain]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="dei_EntityDomain_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Entity</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_BuildingMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Building [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_BuildingMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Premises [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ComponentsOfIncomeTaxExpenseBenefitContinuingOperationsAbstract_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Components of Income Tax Expense (Benefit), Continuing Operations [Abstract]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AvailableForSaleSecuritiesDebtMaturitiesAfterTenYearsFairValue_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Debt Securities, Available-for-Sale, Fair Value, Maturity, Allocated and Single Maturity Date, after Year 10</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AvailableForSaleSecuritiesDebtMaturitiesAfterTenYearsFairValue_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Available-for-sale, maturing after ten years, estimated fair value</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ScheduleOfInvestmentsLineItems_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Schedule of Investments [Line Items]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ScheduleOfInvestmentsLineItems_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Schedule Of Investments [Line Items]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_ScheduleOfAmortizedCostBasisOfCollateralDependentLoansTableTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Schedule of Amortized Cost Basis of Collateral Dependent Loans</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_ScheduleOfAmortizedCostBasisOfCollateralDependentLoansTableTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Schedule of Amortized Cost Basis of Collateral Dependent Loans [Table Text Block]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_ScheduleOfAmortizedCostBasisOfCollateralDependentLoansTableTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Schedule of amortized cost basis of collateral dependent loans.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_PercentageOfLoansAndLeasesCurrent_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Percentage of loans and leases current.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_PercentageOfLoansAndLeasesCurrent_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Percentage Of Loans And Leases Current</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_PercentageOfLoansAndLeasesCurrent_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">As a percentage of total loans, Current</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LoanRestructuringModificationAxis_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Loan Restructuring Modification [Axis]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LoanRestructuringModificationAxis_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Loan Restructuring Modification</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_EmployeeBenefitPlanTable_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Employee Benefit Plan [Table]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_EmployeeBenefitPlanTable_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Employee benefit plan table.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_CurrentStateAndLocalTaxExpenseBenefit_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Current State and Local Tax Expense (Benefit)</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_CurrentStateAndLocalTaxExpenseBenefit_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">State</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="cyd_CybersecurityRiskManagementExpertiseOfManagementResponsibleTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Cybersecurity Risk Management Expertise of Management Responsible [Text Block]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ScheduleOfFederalHomeLoanBankAdvancesByBranchOfFHLBBankTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Federal Home Loan Bank, Advance, Branch of FHLBank [Table Text Block]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ScheduleOfFederalHomeLoanBankAdvancesByBranchOfFHLBBankTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Schedule of Available Unused Lines of Credit</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_HeldToMaturitySecuritiesContinuousUnrealizedLossPositionLessThanTwelveMonthsFairValue_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Debt Securities, Held-to-Maturity, Continuous Unrealized Loss Position, Less than 12 Months, Fair Value</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_HeldToMaturitySecuritiesContinuousUnrealizedLossPositionLessThanTwelveMonthsFairValue_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Held-to-maturity, less than 12 months, fair value</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_TreasuryStockValue_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Treasury Stock, Value</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_TreasuryStockValue_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Treasury Stock, Value, Total</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_TreasuryStockValue_lbl" xlink:role="http://www.xbrl.org/2009/role/negatedLabel">Less treasury stock: 2,247,607 and 2,144,177 shares at cost, respectively</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ProceedsFromSaleOfOtherRealEstate_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Proceeds from Sale of Other Real Estate</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ProceedsFromSaleOfOtherRealEstate_lbl" xlink:role="http://www.xbrl.org/2009/role/negatedLabel">Sales proceeds</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FederalHomeLoanBankAdvancesLongTerm_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Long-Term Federal Home Loan Bank Advances</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FederalHomeLoanBankAdvancesLongTerm_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Long-term Federal Home Loan Bank advances</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FederalHomeLoanBankAdvancesLongTerm_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Long-Term Federal Home Loan Bank Advances, Total</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Related and Nonrelated Parties [Axis]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_CustomerRelatedInterestRateSwapsThirdPartyCounterpartiesMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Customer Related Interest Rate Swaps Third Party Counterparties [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_CustomerRelatedInterestRateSwapsThirdPartyCounterpartiesMember_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Customer related interest rate swaps third party counterparties.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_IncomeTaxReconciliationOtherAdjustments_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Effective Income Tax Rate Reconciliation, Other Adjustments, Amount</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_IncomeTaxReconciliationOtherAdjustments_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Other</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FinancingReceivableOriginatedInCurrentFiscalYear_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Financing Receivable, Year One, Originated, Current Fiscal Year</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FinancingReceivableOriginatedInCurrentFiscalYear_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">2025</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_CollateralAxis_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Collateral Held [Axis]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_CollateralAxis_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Collateral Held</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_CashAndDueFromBanks_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Cash and Due from Banks</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_CashAndDueFromBanks_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Cash and due from banks</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_CashAndDueFromBanks_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Cash and Due from Banks, Total</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_PastDueFinancingReceivablesTableTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Financing Receivable, Past Due [Table Text Block]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_PastDueFinancingReceivablesTableTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Aging Analysis of Past Due Loans</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_PropertyPlantAndEquipmentPolicyTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Property, Plant and Equipment, Policy [Policy Text Block]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_PropertyPlantAndEquipmentPolicyTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Premises and Equipment</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="dei_EntityAddressCityOrTown_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Entity Address, City or Town</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="dei_EntityAddressCityOrTown_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Entity Address, City or Town</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_BalanceSheetRelatedDisclosuresLineItems_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Balance Sheet Related Disclosures [Line Items]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_BalanceSheetRelatedDisclosuresLineItems_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Balance Sheet Related Disclosures.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_NumberOfReportableSegments_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Number of Reportable Segments</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_NumberOfReportableSegments_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Number of reportable segments</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="dei_SecurityExchangeName_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Security Exchange Name</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="dei_SecurityExchangeName_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Security Exchange Name</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_InterestExpenseDeposits_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Interest Expense, Deposits</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_InterestExpenseDeposits_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Interest on deposits</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_InterestExpenseDeposits_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Interest Expense, Deposits, Total</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_ScheduleOfInvestmentSecuritiesAvailableForSaleAndHeldToMaturityTableTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Tabular disclosure of investment securities available for sale and held to maturity.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_ScheduleOfInvestmentSecuritiesAvailableForSaleAndHeldToMaturityTableTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Schedule Of Investment Securities Available For Sale And Held To Maturity Table [Text Block]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_ScheduleOfInvestmentSecuritiesAvailableForSaleAndHeldToMaturityTableTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Schedule of Investment Securities Available-for-Sale and Held-to-Maturity</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_PropertyPlantAndEquipmentGross_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Property, Plant and Equipment, Gross</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_PropertyPlantAndEquipmentGross_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Premises and equipment, gross</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_PropertyPlantAndEquipmentGross_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Property, Plant and Equipment, Gross, Total</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_PropertyPlantAndEquipmentGross_lbl" xlink:role="http://www.xbrl.org/2003/role/periodStartLabel">Property, Plant and Equipment, Gross, Beginning Balance</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_PropertyPlantAndEquipmentGross_lbl" xlink:role="http://www.xbrl.org/2003/role/periodEndLabel">Property, Plant and Equipment, Gross, Ending Balance</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_ScheduleOfIncomeTaxesPaidNetOfRefundsTableTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Schedule of Income Taxes Paid, Net of Refunds [Table Text Block]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_ScheduleOfIncomeTaxesPaidNetOfRefundsTableTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Schedule of income taxes paid, net of refunds.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_ScheduleOfIncomeTaxesPaidNetOfRefundsTableTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Schedule of Income Taxes Paid Net of Refunds</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_NoninterestExpenseAbstract_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Noninterest Expense [Abstract]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_NoninterestExpenseAbstract_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Non-interest expense:</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_NumberOfInterestRateSwapContractsTerminated_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Number of Interest Rate Swap Contracts Terminated</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_NumberOfInterestRateSwapContractsTerminated_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Number of interest rate swap contracts terminated.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_NumberOfInterestRateSwapContractsTerminated_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Number of interest rate swap contracts terminated</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_RealEstate1Member_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Represents information pertaining to real estate.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_RealEstate1Member_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Real Estate1 [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_RealEstate1Member_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Real Estate [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_EmployeeBenefitPlanLineItems_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Employee Benefit Plan [Line Items]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_EmployeeBenefitPlanLineItems_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Employee benefit plan.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_IntersegmentEliminationMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Intersegment Eliminations [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_IntersegmentEliminationMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Intersegment Eliminations [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Income (Loss) from Continuing Operations before Income Taxes, Noncontrolling Interest</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Income before income taxes</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Income before provision for income taxes</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FinancingReceivableAllowanceForCreditLossesCollectivelyEvaluatedForImpairment_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Financing Receivable, Allowance for Credit Loss, Collectively Evaluated</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FinancingReceivableAllowanceForCreditLossesCollectivelyEvaluatedForImpairment_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Collectively evaluated for impairment</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_NonEmployeeDirectorsMember_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Non-employee directors.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_NonEmployeeDirectorsMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Non Employee Directors [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_NonEmployeeDirectorsMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Non-employee Directors [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_CompensationRelatedCostsAbstract_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Compensation Related Costs [Abstract]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_PledgingPurposeDomain_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Pledging Purpose [Domain]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_CommonEquityTierOneRiskBasedCapitalRequiredToBeWellCapitalizedToRiskWeightedAsset_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Common equity tier one risk based capital required to be well capitalized to risk weighted asset.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_CommonEquityTierOneRiskBasedCapitalRequiredToBeWellCapitalizedToRiskWeightedAsset_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Common Equity Tier One Risk Based Capital Required To Be Well Capitalized To Risk Weighted Asset</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_CommonEquityTierOneRiskBasedCapitalRequiredToBeWellCapitalizedToRiskWeightedAsset_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Common equity Tier 1 capital (to risk-weighted assets), To Be Well Capitalized</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_MeasurementInputTypeDomain_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Measurement Input Type [Domain]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_MeasurementInputTypeDomain_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Measurement Input Type</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FinancialAssetNotPastDueMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Financial Asset, Not Past Due [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FinancialAssetNotPastDueMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Current</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Cash, Cash Equivalent, Restricted Cash, and Restricted Cash Equivalent, Continuing Operation</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents_lbl" xlink:role="http://www.xbrl.org/2003/role/periodEndLabel">Cash and cash equivalents, end of period</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents_lbl" xlink:role="http://www.xbrl.org/2003/role/periodStartLabel">Cash and cash equivalents, beginning of period</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Cash, Cash Equivalents, Restricted Cash, and Restricted Cash Equivalents, Total</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_CoreDepositsMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Core Deposits [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_CoreDepositsMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Core Deposits [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_InterestPaidNet_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Interest Paid, Excluding Capitalized Interest, Operating Activity</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_InterestPaidNet_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Interest</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FairValueByMeasurementBasisAxis_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Measurement Basis [Axis]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FairValueByMeasurementBasisAxis_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Measurement Basis</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="srt_RangeMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Statistical Measurement [Domain]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="srt_RangeMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Statistical Measurement</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_OtherOperatingIncomeAndExpenseTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Other Operating Income and Expense [Text Block]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_OtherOperatingIncomeAndExpenseTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Other Operating Income and Expense</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AllocatedShareBasedCompensationExpense_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Share-Based Payment Arrangement, Expense</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AllocatedShareBasedCompensationExpense_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Share-based payment arrangement, expense</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="dei_DocumentPeriodEndDate_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Document Period End Date</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="dei_DocumentPeriodEndDate_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Document Period End Date</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_OtherIncomeAndExpensesAbstract_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Other Income and Expenses [Abstract]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="srt_TitleOfIndividualAxis_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Title and Position [Axis]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="srt_TitleOfIndividualAxis_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Title of Individual</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FairValueMeasurementsFairValueHierarchyDomain_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Fair Value Hierarchy and NAV</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FairValueMeasurementsFairValueHierarchyDomain_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Fair Value Hierarchy and NAV [Domain]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="dei_IcfrAuditorAttestationFlag_lbl" xlink:role="http://www.xbrl.org/2003/role/label">ICFR Auditor Attestation Flag</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="dei_IcfrAuditorAttestationFlag_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">ICFR Auditor Attestation Flag</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_LongTermDebtWeightedAverageRemainingMaturityTerm_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Long term debt weighted average remaining maturity term.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_LongTermDebtWeightedAverageRemainingMaturityTerm_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Long Term Debt Weighted Average Remaining Maturity Term</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_LongTermDebtWeightedAverageRemainingMaturityTerm_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Weighted average remaining maturity (in years)</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_InterestOnDepositsMember_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Interest on deposits member.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_InterestOnDepositsMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Interest On Deposits [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_InterestOnDepositsMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Interest on Deposits [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableNumber_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Exercisable, Number</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableNumber_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Options exercisable, end of year (in shares)</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_ThePeoplesBankMember_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Represents information regarding The Peoples Bank.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_ThePeoplesBankMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">The Peoples Bank [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_ThePeoplesBankMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">The Peoples Bank [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_ForwardInterestRateSwapContractsMember_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Forward interest rate swap contracts member.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_ForwardInterestRateSwapContractsMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Forward Interest Rate Swap Contracts [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_ForwardInterestRateSwapContractsMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Forward Interest Rate Swap Contracts [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_CreditLossStatusDomain_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Credit Loss Status [Domain]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_CreditLossStatusDomain_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Credit Loss Status</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_OrganizationConsolidationAndPresentationOfFinancialStatementsLineItems_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Organization consolidation and presentation of financial statements.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_OrganizationConsolidationAndPresentationOfFinancialStatementsLineItems_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Organization Consolidation And Presentation Of Financial Statements [Line Items]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_OrganizationConsolidationAndPresentationOfFinancialStatementsLineItems_lbl" xlink:role="http://www.xbrl.org/2003/role/verboseLabel">Organization Consolidation And Presentation Of Financial Statements [Line Items]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DebtInstrumentDescriptionOfVariableRateBasis_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Debt Instrument, Description of Variable Rate Basis</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DebtInstrumentDescriptionOfVariableRateBasis_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Variable rate, description</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_StatementOfFinancialPositionAbstract_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Statement of Financial Position [Abstract]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LossContingenciesByNatureOfContingencyAxis_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Loss Contingency Nature [Axis]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LossContingenciesByNatureOfContingencyAxis_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Loss Contingency Nature</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_PercentageOfLoanPortfolio_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Percentage of loan portfolio.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_PercentageOfLoanPortfolio_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Percentage Of Loan Portfolio</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_PercentageOfLoanPortfolio_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Percentage of Loan Portfolio</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_RevenueRecognitionPolicyTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Revenue [Policy Text Block]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_RevenueRecognitionPolicyTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Revenue Recognition</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LossContingencyNatureDomain_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Loss Contingency, Nature [Domain]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LossContingencyNatureDomain_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Loss Contingency, Nature</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_DerivativeInstrumentInterestRateIncreaseDecrease_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Derivative Instrument, Interest Rate, Increase (Decrease)</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_DerivativeInstrumentInterestRateIncreaseDecrease_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Derivative instrument, interest rate, increase (decrease).</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_DerivativeInstrumentInterestRateIncreaseDecrease_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Derivative instrument, interest rate, increase (decrease)</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_NumberOfForwardInterestRateSwapContracts_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Number of forward interest rate swap contracts.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_NumberOfForwardInterestRateSwapContracts_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Number Of Forward Interest Rate Swap Contracts</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_NumberOfForwardInterestRateSwapContracts_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Number of forward interest rate swap contracts</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_CompensationAndEmployeeBenefitPlansTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Compensation and Employee Benefit Plans [Text Block]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_CompensationAndEmployeeBenefitPlansTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Deferred Compensation Plans</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_CollectionAndRecoveries_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Collection and recoveries.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_CollectionAndRecoveries_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Collection And Recoveries</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_CollectionAndRecoveries_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Collection and recoveries</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_OtherAssetsFairValueDisclosure_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Other Assets Held for Sale</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_OtherAssetsFairValueDisclosure_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Other Assets, Fair Value Disclosure</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_CurrentIncomeTaxExpenseBenefit_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Current Income Tax Expense (Benefit)</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_CurrentIncomeTaxExpenseBenefit_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Total current taxes</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="cyd_CybersecurityRiskManagementStrategyAndGovernanceLineItems_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Cybersecurity Risk Management, Strategy, and Governance [Line Items]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_NondesignatedMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Not Designated as Hedging Instrument [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_NondesignatedMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Derivatives Not Designated as Hedging Instruments [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FinancingReceivablesPeriodPastDueDomain_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Financial Asset, Aging [Domain]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FinancingReceivablesPeriodPastDueDomain_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Financial Asset, Aging</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_IncreaseDecreaseInDeposits_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Net increase in customer deposits</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_IncreaseDecreaseInDeposits_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Increase (Decrease) in Deposits</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_IncreaseDecreaseInDeposits_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Increase (Decrease) in Deposits, Total</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FairValuesDerivativesBalanceSheetLocationByDerivativeContractTypeByHedgingDesignationTable_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Fair Values Derivatives, Balance Sheet Location, by Derivative Contract Type [Table]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FairValuesDerivativesBalanceSheetLocationByDerivativeContractTypeByHedgingDesignationTable_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Fair Values Derivatives Balance Sheet Location By Derivative Contract Type By Hedging Designation [Table]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_Liabilities_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Liabilities</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_Liabilities_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Total liabilities</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Financial Instruments [Domain]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Financial Instruments</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ScheduleOfFairValueOffBalanceSheetRisksTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Schedule of Fair Value, off-Balance-Sheet Risks [Table Text Block]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ScheduleOfFairValueOffBalanceSheetRisksTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Summary of Commitment and Contingent Liabilities</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_DistributionsInExcessOfUndistributedIncomeLossOfSubsidiaries_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Distributions in excess of undistributed income loss of subsidiaries.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_DistributionsInExcessOfUndistributedIncomeLossOfSubsidiaries_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Distributions In Excess Of Undistributed Income Loss Of Subsidiaries</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_DistributionsInExcessOfUndistributedIncomeLossOfSubsidiaries_lbl" xlink:role="http://www.xbrl.org/2009/role/negatedLabel">Distributions in excess of undistributed income of subsidiary</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_HeldToMaturitySecuritiesDebtMaturitiesWithinOneYearNetCarryingAmount_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Debt Securities, Held-to-Maturity, Amortized Cost, after Allowance for Credit Loss, Maturity, Allocated and Single Maturity Date, Year One</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_HeldToMaturitySecuritiesDebtMaturitiesWithinOneYearNetCarryingAmount_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Held-to-maturity, maturing within one year, amortized cost</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_HeldToMaturitySecuritiesDebtMaturitiesWithinOneYearFairValue_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Debt Securities, Held-to-Maturity, Fair Value, Maturity, Allocated and Single Maturity Date, Year One</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_HeldToMaturitySecuritiesDebtMaturitiesWithinOneYearFairValue_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Held-to-maturity, maturing within one year, estimated fair value</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_BankOwnedLifeInsurancePolicyTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Bank owned life insurance policy text block.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_BankOwnedLifeInsurancePolicyTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Bank Owned Life Insurance Policy [Text Block]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_BankOwnedLifeInsurancePolicyTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Bank Owned Life Insurance</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DerivativeLiabilityStatementOfFinancialPositionExtensibleEnumeration_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Derivative Liability, Statement of Financial Position [Extensible Enumeration]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearTwo_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">2027</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearTwo_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Lessee, Operating Lease, Liability, to be Paid, Year Two</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DerivativeInstrumentsGainLossLineItems_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Derivative Instruments, Gain (Loss) [Line Items]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DerivativeInstrumentsGainLossLineItems_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Derivative Instruments Gain Loss [Line Items]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_InterestRateDerivativeLiabilitiesAtFairValue_lbl" xlink:role="http://www.xbrl.org/2003/role/verboseLabel">Other liabilities - interest rate swaps</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_InterestRateDerivativeLiabilitiesAtFairValue_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Derivative contracts, liabilities at fair value</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_InterestRateDerivativeLiabilitiesAtFairValue_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Interest Rate Derivative Liabilities, at Fair Value</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FinancingReceivableCreditQualityIndicatorsTableTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Financing Receivable Credit Quality Indicators [Table Text Block]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FinancingReceivableCreditQualityIndicatorsTableTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Loans By Credit Quality Indicators</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_RestrictedStockMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Restricted Stock [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_RestrictedStockMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Restricted Stock [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_RestrictedStockMember_lbl" xlink:role="http://www.xbrl.org/2003/role/verboseLabel">Restricted Stock Award [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_SegmentReportingDisclosureOfEntitysReportableSegmentsAbstract_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Segment Reporting, Disclosure of Entity's Reportable Segments [Abstract]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_VariableRateAxis_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Variable Rate [Axis]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FairValueDisclosureOffbalanceSheetRisksAmountLiability_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Fair Value Disclosure, off-Balance-Sheet Risks, Amount, Liability</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FairValueDisclosureOffbalanceSheetRisksAmountLiability_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Commitments and contingent liabilities</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FiniteLivedIntangibleAssetsGross_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Finite-Lived Intangible Assets, Gross</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FiniteLivedIntangibleAssetsGross_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Gross carrying amount</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FiniteLivedIntangibleAssetsGross_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Finite-Lived Intangible Assets, Gross, Total</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_AmortizedCostBasisOfClosedPortfoliosUsedInHedgingRelationships_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Amortized cost basis of closed portfolios used in hedging relationships.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_AmortizedCostBasisOfClosedPortfoliosUsedInHedgingRelationships_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Amortized Cost Basis Of Closed Portfolios Used In Hedging Relationships</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_AmortizedCostBasisOfClosedPortfoliosUsedInHedgingRelationships_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Amortized cost basis of closed portfolios used in hedging relationships</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPositionLessThan12MonthsAccumulatedLoss_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Debt Securities, Available-for-Sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPositionLessThan12MonthsAccumulatedLoss_lbl" xlink:role="http://www.xbrl.org/2009/role/negatedLabel">Available-for-sale, less than 12 months, unrealized losses</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPosition12MonthsOrLongerNumberOfPositions_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Debt Securities, Available-for-Sale, Continuous Unrealized Loss Position, 12 Months or Longer, Number of Positions</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPosition12MonthsOrLongerNumberOfPositions_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Available-for-sale, Securities in Unrealized Loss Positions, Qualitative Disclosure, Number of Positions, Greater than or Equal to One Year</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_WeightedAverageNumberOfDilutedSharesOutstanding_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Weighted Average Number of Shares Outstanding, Diluted</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_WeightedAverageNumberOfDilutedSharesOutstanding_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Diluted shares</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="dei_EntityFileNumber_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Securities Act File Number</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="dei_EntityFileNumber_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Entity File Number</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_InterestRateSwapsRelatedToFixedRateIndirectConsumerLoansMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Interest Rate Swaps Related To Fixed Rate Indirect Consumer Loans [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_InterestRateSwapsRelatedToFixedRateIndirectConsumerLoansMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Interest Rate Swaps Related To Fixed Rate Indirect Consumer Loans [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_InterestRateSwapsRelatedToFixedRateIndirectConsumerLoansMember_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Interest rate swaps related to fixed rate indirect consumer loans.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_RelatedPartyDepositLiabilities_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Related Party Deposit Liabilities</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_RelatedPartyDepositLiabilities_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Related Party Deposit Liabilities</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodNetOfTax_lbl" xlink:role="http://www.xbrl.org/2003/role/label">OCI, Debt Securities, Available-for-Sale, Unrealized Holding Gain (Loss), before Adjustment, after Tax</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodNetOfTax_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Unrealized holding gains on securities available-for-sale arising during the year, net of tax expense of $1436 and $656, respectively</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_EffectiveIncomeTaxRateReconciliationOtherReconcilingItemsPercent_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Effective Income Tax Rate Reconciliation, Other Reconciling Items, Percent</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_EffectiveIncomeTaxRateReconciliationOtherReconcilingItemsPercent_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Other reconciling items</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_NumberOfInvestmentPortfolios_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Represents the number of investment portfolios.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_NumberOfInvestmentPortfolios_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Number Of Investment Portfolios</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_NumberOfInvestmentPortfolios_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Number of investment portfolios</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_OtherAssets_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Other Assets</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_OtherAssets_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Other assets</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_OtherAssets_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Other Assets, Total</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="dei_CoverAbstract_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Cover [Abstract]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_OtherLiabilitiesInterestRateSwapsMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Other Liabilities Interest Rate Swaps [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_OtherLiabilitiesInterestRateSwapsMember_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Other liabilities interest rate swaps.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DeferredFederalStateAndLocalTaxExpenseBenefitAbstract_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Deferred Federal, State and Local, Tax Expense (Benefit) [Abstract]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DeferredFederalStateAndLocalTaxExpenseBenefitAbstract_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Deferred taxes</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_MeasurementInputTypeAxis_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Measurement Input Type [Axis]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_MeasurementInputTypeAxis_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Measurement Input Type</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeitedInPeriod_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Forfeited in Period</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeitedInPeriod_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Forfeited (in shares)</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_CapitalRequiredForCapitalAdequacyToRiskWeightedAssets_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Banking Regulation, Total Risk-Based Capital Ratio, Capital Adequacy, Minimum</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_CapitalRequiredForCapitalAdequacyToRiskWeightedAssets_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Total capital (to risk-weighted assets), Minimum Requirement</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_SubordinatedDebtMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Subordinated Debt [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_SubordinatedDebtMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Subordinated Debt [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FinancingReceivablesPeriodPastDueAxis_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Financial Asset, Aging</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FinancingReceivablesPeriodPastDueAxis_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Financial Asset, Aging [Axis]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_DepreciationAndAmortizationOfPropertyPlantAndEquipmentAndComputerPrograms_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Depreciation and amortization of property, plant, and equipment and computer programs.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_DepreciationAndAmortizationOfPropertyPlantAndEquipmentAndComputerPrograms_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Depreciation And Amortization Of Property Plant And Equipment And Computer Programs</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_DepreciationAndAmortizationOfPropertyPlantAndEquipmentAndComputerPrograms_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Depreciation and amortization</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DerivativeGainLossOnDerivativeNet_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Derivative, Gain (Loss) on Derivative, Net</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DerivativeGainLossOnDerivativeNet_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Estimated Fair Value Gain (Loss)</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DerivativeGainLossOnDerivativeNet_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Derivative, Gain (Loss) on Derivative, Net, Total</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="srt_ScenarioUnspecifiedDomain_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Scenario [Domain]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="srt_ScenarioUnspecifiedDomain_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Scenario</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_RealEstateAcquiredThroughForeclosure_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Real Estate Acquired Through Foreclosure</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_RealEstateAcquiredThroughForeclosure_lbl" xlink:role="http://www.xbrl.org/2003/role/periodEndLabel">Ending balance</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_RealEstateAcquiredThroughForeclosure_lbl" xlink:role="http://www.xbrl.org/2003/role/periodStartLabel">Beginning balance</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_RealEstateAcquiredThroughForeclosure_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Other real estate owned</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_USTreasurySecuritiesMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">US Treasury Securities [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_USTreasurySecuritiesMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">US Treasury Securities [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ImpairedFinancingReceivablesTableTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Loans Individually Evaluated, as well as any Related Allowance for Loans and Lease Losses</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ImpairedFinancingReceivablesTableTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Impaired Financing Receivables [Table Text Block]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_SaleOfStockNameOfTransactionDomain_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Sale of Stock [Domain]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_SaleOfStockNameOfTransactionDomain_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Sale of Stock</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_SegmentReportingDisclosureTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Segment Reporting Disclosure [Text Block]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_SegmentReportingDisclosureTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Segment Reporting</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_NonvestedRestrictedStockSharesActivityTableTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Nonvested Restricted Stock Shares Activity [Table Text Block]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_NonvestedRestrictedStockSharesActivityTableTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Restricted Stock Award Activity</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_RevenueFromContractWithCustomerIncludingAssessedTax_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Revenue from Contract with Customer, Including Assessed Tax</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_RevenueFromContractWithCustomerIncludingAssessedTax_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Revenue from Contract with Customer, Including Assessed Tax</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_RevenueFromContractWithCustomerIncludingAssessedTax_lbl" xlink:role="http://www.xbrl.org/2003/role/verboseLabel">Total income</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_RevenueFromContractWithCustomerIncludingAssessedTax_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Total income</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DividendPaymentRestrictionsScheduleDescription_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Dividend Payment Restriction and Statutory Capital and Surplus Requirements, Description</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DividendPaymentRestrictionsScheduleDescription_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Dividend payment restrictions schedule, description</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_StandbyLettersOfCreditMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Standby Letters of Credit [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_StandbyLettersOfCreditMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Standby Letters of Credit [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_UnusedLinesOfCreditMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Unused lines of Credit [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_UnusedLinesOfCreditMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Unused lines of Credit [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ProceedsFromMaturitiesPrepaymentsAndCallsOfHeldToMaturitySecurities_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Proceeds from Maturities, Prepayments and Calls of Held-to-Maturity Securities</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ProceedsFromMaturitiesPrepaymentsAndCallsOfHeldToMaturitySecurities_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Proceeds from maturities and prepayments of investment securities, held-to-maturity</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DeferredTaxAssetsOther_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Deferred Tax Assets, Other</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DeferredTaxAssetsOther_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Other</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_CurrentFederalStateAndLocalTaxExpenseBenefitAbstract_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Current Federal, State and Local, Tax Expense (Benefit) [Abstract]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_CurrentFederalStateAndLocalTaxExpenseBenefitAbstract_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Current taxes</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ShortTermDebtTypeDomain_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Short-Term Debt, Type [Domain]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ShortTermDebtTypeDomain_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Short-term Debt, Type</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FiniteLivedIntangibleAssetsNet_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Finite-Lived Intangible Assets, Net</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FiniteLivedIntangibleAssetsNet_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Finite-Lived Intangible Assets, Net, Ending Balance</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FiniteLivedIntangibleAssetsNet_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Core deposit intangible, net</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FiniteLivedIntangibleAssetsNet_lbl" xlink:role="http://www.xbrl.org/2003/role/periodStartLabel">Finite-Lived Intangible Assets, Net, Beginning Balance</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FiniteLivedIntangibleAssetsNet_lbl" xlink:role="http://www.xbrl.org/2003/role/periodEndLabel">Finite-Lived Intangible Assets, Net, Ending Balance</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_CapitalRequiredToBeWellCapitalizedToRiskWeightedAssets_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Banking Regulation, Total Risk-Based Capital Ratio, Well Capitalized, Minimum</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_CapitalRequiredToBeWellCapitalizedToRiskWeightedAssets_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Total capital (to risk-weighted assets), To Be Well Capitalized</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_IncomeTaxReconciliationChangeInEnactedTaxRate_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Apportionment and state rate changes</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_IncomeTaxReconciliationChangeInEnactedTaxRate_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Effective Income Tax Rate Reconciliation, Change in Enacted Tax Rate, Amount</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_OtherIncomeAndExpensesLineItems_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Other Income and Expenses [Line Items]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_OtherIncomeAndExpensesLineItems_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Other income and expenses.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_PledgedStatusDomain_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Pledged Status [Domain]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DebtSecuritiesAvailableForSaleAccruedInterestAfterAllowanceForCreditLoss_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Debt Securities, Available-for-Sale, Accrued Interest, after Allowance for Credit Loss</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DebtSecuritiesAvailableForSaleAccruedInterestAfterAllowanceForCreditLoss_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Debt Securities, Available-for-Sale, Accrued Interest, after Allowance for Credit Loss, Total</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DebtSecuritiesAvailableForSaleAccruedInterestAfterAllowanceForCreditLoss_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Available-for-sale securities accrued interest receivable</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_BrokeredCertificatesOfDeposit_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Represents brokered certificates of deposit.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_BrokeredCertificatesOfDeposit_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Brokered Certificates Of Deposit</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_BrokeredCertificatesOfDeposit_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Brokered Certificates of Deposit</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_RestructuringCharges_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Restructuring Charges</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_RestructuringCharges_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Pre-tax charges of restructuring</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_RestructuringCharges_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Total expenses</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_PropertyPlantAndEquipmentUsefulLife_lbl" xlink:role="http://www.xbrl.org/2003/role/verboseLabel">Useful lives of premises and equipment</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_PropertyPlantAndEquipmentUsefulLife_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Property, Plant and Equipment, Useful Life</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_PropertyPlantAndEquipmentUsefulLife_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Useful lives for all premises and equipment (Year)</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ShortTermDebtTypeAxis_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Short-Term Debt, Type [Axis]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ShortTermDebtTypeAxis_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Short-term Debt, Type</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ScheduleOfInvestmentsTable_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Schedule of Investments [Table]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ScheduleOfInvestmentsTable_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Schedule Of Investments [Table]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_NewAccountingPronouncementsPolicyPolicyTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/label">New Accounting Pronouncements, Policy [Policy Text Block]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_NewAccountingPronouncementsPolicyPolicyTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Accounting Standards Recently Adopted/ Not Yet Adopted</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LesseeOperatingLeaseLiabilityMaturityTableTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Lessee, Operating Lease, Liability, to be Paid, Maturity [Table Text Block]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LesseeOperatingLeaseLiabilityMaturityTableTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Future Minimum Operating Lease Payments</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipByIncomeStatementLocationByDerivativeInstrumentRiskTable_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Derivative Instruments, Gain (Loss) [Table]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipByIncomeStatementLocationByDerivativeInstrumentRiskTable_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Derivative Instruments Gain Loss By Hedging Relationship By Income Statement Location By Derivative Instrument Risk [Table]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_OtherThanTemporaryImpairmentLossDebtSecuritiesAvailableForSaleRecognizedInEarnings_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Other-than-temporary Impairment Loss, Debt Securities, Available-for-Sale, Recognized in Earnings</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_OtherThanTemporaryImpairmentLossDebtSecuritiesAvailableForSaleRecognizedInEarnings_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Other than Temporary Impairment Losses, Investments, Portion Recognized in Earnings, Net, Total</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_AllowanceForLoanAndLeaseLossesWriteOffsTwoYearsBeforeLatestFiscalYear_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Allowance For Loan And Lease Losses Write Offs Two Years Before Latest Fiscal Year</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_AllowanceForLoanAndLeaseLossesWriteOffsTwoYearsBeforeLatestFiscalYear_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Allowance for loan and lease losses write offs two years before latest fiscal year</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_AllowanceForLoanAndLeaseLossesWriteOffsTwoYearsBeforeLatestFiscalYear_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Current period gross charge-offs, 2023</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPeriod1_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Share-Based Compensation Arrangement by Share-Based Payment Award, Award Vesting Period</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPeriod1_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Share-based compensation arrangement by share-based payment award, award vesting period</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_UnrecognizedTaxBenefitsPeriodIncreaseDecrease_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Unrecognized Tax Benefits, Period Increase (Decrease)</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_UnrecognizedTaxBenefitsPeriodIncreaseDecrease_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Unrecognized Tax Benefits, Period Increase (Decrease), Total</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_UnrecognizedTaxBenefitsPeriodIncreaseDecrease_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Unrecognized Tax Benefits, Period Increase (Decrease), Total</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DeferredTaxAssetsTaxDeferredExpenseReservesAndAccrualsProvisionForLoanLosses_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Allowance for credit losses</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DeferredTaxAssetsTaxDeferredExpenseReservesAndAccrualsProvisionForLoanLosses_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Deferred Tax Asset, Tax Deferred Expense, Reserve and Accrual, Financing Receivable, Allowance for Credit Loss</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ProvisionForLoanAndLeaseLosses_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Provision for credit losses</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ProvisionForLoanAndLeaseLosses_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Provision for Loan and Lease Losses</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesDomestic_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Income (Loss) from Continuing Operations before Income Taxes, Domestic</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesDomestic_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Domestic</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_CommercialAndIndustrialLoansAndLeasesMember_lbl" xlink:role="http://www.xbrl.org/2003/role/verboseLabel">Commercial and Industrial Loans [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_CommercialAndIndustrialLoansAndLeasesMember_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Commercial and industrial loans and leases.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_CommercialAndIndustrialLoansAndLeasesMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Commercial And Industrial Loans And Leases [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_CommercialAndIndustrialLoansAndLeasesMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Commercial and Industrial Loans and Leases [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_IncomeTaxExpenseBenefitContinuingOperationsIncomeTaxReconciliationAbstract_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Income Tax Expense (Benefit), Effective Income Tax Rate Reconciliation, Amount [Abstract]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_IncomeTaxExpenseBenefitContinuingOperationsIncomeTaxReconciliationAbstract_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Increase (decrease) resulting from:</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_CarryingReportedAmountFairValueDisclosureMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Reported Value Measurement [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_CarryingReportedAmountFairValueDisclosureMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Carrying Amount [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_SuppliesAndPostageExpense_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Supplies and Postage Expense</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_SuppliesAndPostageExpense_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Postage, stationery and supplies</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_SuppliesAndPostageExpense_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Supplies and Postage Expense, Total</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_PercentageOfLoansAndLeases_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Percentage of loans and leases.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_PercentageOfLoansAndLeases_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Percentage Of Loans And Leases</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_PercentageOfLoansAndLeases_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">As a percentage of total loans</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_ProceedsFromPaymentsRelatedToTaxWithholdingForShareBasedCompensation_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Net share-based compensation transactions</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_ProceedsFromPaymentsRelatedToTaxWithholdingForShareBasedCompensation_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Proceeds from Payments Related To Tax Withholding For Share Based Compensation</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_ProceedsFromPaymentsRelatedToTaxWithholdingForShareBasedCompensation_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Proceeds from payments related to tax withholding for share based compensation.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_CommonStockSharesOutstanding_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Common Stock, Shares, Outstanding</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_CommonStockSharesOutstanding_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Common stock, shares outstanding (in shares)</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_CommonStockSharesOutstanding_lbl" xlink:role="http://www.xbrl.org/2003/role/periodStartLabel">Common Stock, Shares, Outstanding, Beginning Balance</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_CommonStockSharesOutstanding_lbl" xlink:role="http://www.xbrl.org/2003/role/periodEndLabel">Common Stock, Shares, Outstanding, Ending Balance</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LongTermDebtAverageAmountOutstanding_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Long-Term Debt, Average Amount Outstanding</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LongTermDebtAverageAmountOutstanding_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Average balance during the year</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FinancingReceivableAccruedInterestAfterAllowanceForCreditLossStatementOfFinancialPositionExtensibleList_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Financing Receivable, Accrued Interest, after Allowance for Credit Loss, Statement of Financial Position [Extensible Enumeration]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_RealEstateOwnedTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Real Estate Owned [Text Block]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_RealEstateOwnedTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Other Real Estate Owned and Repossessed Assets</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="dei_DocumentTransitionReport_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Document Transition Report</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="dei_DocumentTransitionReport_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Document Transition Report</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DeferredTaxAssetsLiabilitiesNet_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Deferred Tax Assets, Net</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DeferredTaxAssetsLiabilitiesNet_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Net deferred tax asset, included in other assets</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_InterestAndFeesOnLoansMember_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Interest and fees on Loans member.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_InterestAndFeesOnLoansMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Interest And Fees On Loans [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_InterestAndFeesOnLoansMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Interest and Fees on Loans [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_OperatingExpenses_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Operating Expenses</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_OperatingExpenses_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Expense</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_OperatingExpenses_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Total</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_HeldToMaturitySecuritiesFairValue_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Held-to-maturity, estimated fair value</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_HeldToMaturitySecuritiesFairValue_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Held-to-maturity, amortized cost</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_HeldToMaturitySecuritiesFairValue_lbl" xlink:role="http://www.xbrl.org/2003/role/verboseLabel">Investment securities held-to-maturity</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_HeldToMaturitySecuritiesFairValue_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Held-to-maturity, fair value</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_RestructuringChargesAbstract_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Restructuring Charges [Abstract]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_RestructuringChargesAbstract_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Expense Category</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LesseeOperatingLeasesTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Lessee, Operating Leases [Text Block]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LesseeOperatingLeasesTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Leases</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_PaymentsForRepurchaseOfCommonStock_lbl" xlink:role="http://www.xbrl.org/2009/role/negatedTerseLabel">Treasury stock repurchases</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_PaymentsForRepurchaseOfCommonStock_lbl" xlink:role="http://www.xbrl.org/2009/role/negatedLabel">Repurchases of common stock</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_PaymentsForRepurchaseOfCommonStock_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Payments for Repurchase of Common Stock</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ScheduleOfComponentsOfIncomeTaxExpenseBenefitTableTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Schedule of Components of Income Tax Expense (Benefit) [Table Text Block]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ScheduleOfComponentsOfIncomeTaxExpenseBenefitTableTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Schedule of Components of Income Tax Expense (Benefit)</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ComprehensiveIncomeNetOfTaxIncludingPortionAttributableToNoncontrollingInterest_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Total comprehensive income</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ComprehensiveIncomeNetOfTaxIncludingPortionAttributableToNoncontrollingInterest_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Comprehensive Income (Loss), Net of Tax, Including Portion Attributable to Noncontrolling Interest</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_UnrealizedGainLossOnDerivatives_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Net unrealized gain</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_UnrealizedGainLossOnDerivatives_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Unrealized Gain (Loss) on Derivatives</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_StatementOfCashFlowsAbstract_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Statement of Cash Flows [Abstract]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_CurrentFederalTaxExpenseBenefit_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Current Federal Tax Expense (Benefit)</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_CurrentFederalTaxExpenseBenefit_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Federal</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ScheduleOfShareBasedCompensationStockOptionsActivityTableTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Share-Based Payment Arrangement, Option, Activity [Table Text Block]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ScheduleOfShareBasedCompensationStockOptionsActivityTableTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Stock Option Activity</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_DirectConsumerMember_lbl" xlink:role="http://www.xbrl.org/2003/role/verboseLabel">Direct [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_DirectConsumerMember_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Direct consumer member.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_DirectConsumerMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Direct Consumer [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_DirectConsumerMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Direct Consumer [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_ConstructionLandDevelopmentAndOtherLandLoansMember_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Represents information pertaining to construction, land development and other land loans.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_ConstructionLandDevelopmentAndOtherLandLoansMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Construction Land Development And Other Land Loans [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_ConstructionLandDevelopmentAndOtherLandLoansMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Construction, Land Development and Other Land Loans [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FinancingReceivableNonaccrualStatusLineItems_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Financing Receivable, Nonaccrual [Line Items]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_DefinedContributionPlanDiscretionaryContributionPercent_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Percentage of discretionary contributions made by an employer to a defined contribution plan.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_DefinedContributionPlanDiscretionaryContributionPercent_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Defined Contribution Plan Discretionary Contribution Percent</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_DefinedContributionPlanDiscretionaryContributionPercent_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Defined Contribution Plan, Discretionary Contribution Percent</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_InterestRateSwapMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Interest Rate Swap [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_InterestRateSwapMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Customer-Related Interest Rate Swaps [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_StockholdersEquityNoteDisclosureTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Equity [Text Block]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_StockholdersEquityNoteDisclosureTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Shareholder's Equity</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ScheduleOfAccountsNotesLoansAndFinancingReceivableTable_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Accounts and Financing Receivables [Table]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_GoodwillAndOtherIntangibleAssetTable_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Goodwill and other intangible asset.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_GoodwillAndOtherIntangibleAssetTable_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Goodwill And Other Intangible Asset [Table]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_GoodwillAndOtherIntangibleAssetTable_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Goodwill And Other Intangible Asset [Table]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FiniteLivedIntangibleAssetsLineItems_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Finite-Lived Intangible Assets [Line Items]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FiniteLivedIntangibleAssetsLineItems_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Finite Lived Intangible Assets [Line Items]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_LoansAndInterestIncomePolicyTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Loans and interest income policy text block.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_LoansAndInterestIncomePolicyTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Loans And Interest Income Policy [Text Block]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_LoansAndInterestIncomePolicyTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Loans and Interest Income</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DeferredTaxLiabilitiesOther_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Deferred Tax Liabilities, Other</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DeferredTaxLiabilitiesOther_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Other</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_NetIncomeLoss_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Net income</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_NetIncomeLoss_lbl" xlink:role="http://www.xbrl.org/2003/role/verboseLabel">Net income</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingIntrinsicValue_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Outstanding, Intrinsic Value</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingIntrinsicValue_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Share-based compensation arrangement by share-based payment award, options, outstanding, intrinsic value</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_RepossessionsAssetMeasurementInput_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Repossessions Asset Measurement Input</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_RepossessionsAssetMeasurementInput_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Repossessions asset measurement input.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_RepossessionsAssetMeasurementInput_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Repossessions held-for-sale</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DeferredCompensationArrangementWithIndividualShareBasedPaymentsLineItems_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Deferred Compensation Arrangement with Individual, Share-Based Payments [Line Items]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DeferredCompensationArrangementWithIndividualShareBasedPaymentsLineItems_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Deferred Compensation Arrangement With Individual Share Based Payments [Line Items]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_OperatingLeasePayments_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Operating Lease, Payments</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_OperatingLeasePayments_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Operating cash flows from operating leases</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ProvisionForLoanLeaseAndOtherLosses_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Provision for credit losses</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ProvisionForLoanLeaseAndOtherLosses_lbl" xlink:role="http://www.xbrl.org/2003/role/verboseLabel">Provision for credit losses</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ProvisionForLoanLeaseAndOtherLosses_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Provision for Loan, Lease, and Other Losses</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ProvisionForLoanLeaseAndOtherLosses_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Provision for Loan, Lease, and Other Losses, Total</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DerivativesFairValueLineItems_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Derivatives, Fair Value [Line Items]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DerivativesFairValueLineItems_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Derivatives Fair Value [Line Items]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DebtSecuritiesHeldToMaturityAccruedInterestAfterAllowanceForCreditLoss_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Debt Securities, Held-to-Maturity, Accrued Interest, after Allowance for Credit Loss</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DebtSecuritiesHeldToMaturityAccruedInterestAfterAllowanceForCreditLoss_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Held-to-maturity securities accrued interest receivable</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AssetsAbstract_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Assets [Abstract]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AssetsAbstract_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">ASSETS</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FederalHomeLoanBankStock_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Federal Home Loan Bank Stock</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FederalHomeLoanBankStock_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Federal Home Loan Bank stock, at cost</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ConstructionInProgressMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Construction in Progress [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_TerminationOfTechnologyContracts_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Termination of technology contracts.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_TerminationOfTechnologyContracts_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Termination Of Technology Contracts</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_TerminationOfTechnologyContracts_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Termination of technology contracts</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_RestructuringAndRelatedActivitiesAbstract_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Restructuring and Related Activities [Abstract]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="dei_DocumentFiscalYearFocus_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Document Fiscal Year Focus</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="dei_DocumentFiscalYearFocus_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Document Fiscal Year Focus</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_TroubledDebtRestructuringsOnFinancingReceivablesTableTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Financing Receivable, Modified [Table Text Block]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_TroubledDebtRestructuringsOnFinancingReceivablesTableTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Loans Modified in a Troubled Debt Restructuring</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_LoansAndLeasesHeldForInvestmentPolicyPolicyTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Loans and Leases Held for Investment</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_LoansAndLeasesHeldForInvestmentPolicyPolicyTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Loans and Leases Held for Investment Policy [Policy Text Block]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_LoansAndLeasesHeldForInvestmentPolicyPolicyTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Loans and leases held for investment policy.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DeferredTaxAssetsTaxDeferredExpense_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Deferred Tax Assets, Tax Deferred Expense</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DeferredTaxAssetsTaxDeferredExpense_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Deferred commissions and fees</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DeferredTaxAssetsTaxDeferredExpense_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Deferred Tax Assets, Tax Deferred Expense, Total</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_NetCashProvidedByUsedInInvestingActivitiesAbstract_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Cash Provided by (Used in) Investing Activity, Including Discontinued Operation [Abstract]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_NetCashProvidedByUsedInInvestingActivitiesAbstract_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Cash flows from investing activities:</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_UnfundedLoanCommitmentMember_lbl" xlink:role="http://www.xbrl.org/2003/role/verboseLabel">Reserve for Unfunded Commitments [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_UnfundedLoanCommitmentMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Unfunded Loan Commitment [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_UnfundedLoanCommitmentMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Unfunded Loan Commitment [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_InterestExpenseLongTermDebt_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Interest Expense, Long-Term Debt</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_InterestExpenseLongTermDebt_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Interest on long-term borrowings</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_InterestExpenseLongTermDebt_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Interest Expense, Long-Term Debt, Total</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ScheduleOfIncomeBeforeIncomeTaxDomesticAndForeignTableTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Schedule of Income before Income Tax, Domestic and Foreign [Table Text Block]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ScheduleOfIncomeBeforeIncomeTaxDomesticAndForeignTableTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Schedule of Components of Income Before Provision for Income Taxes by Taxing Jurisdiction</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_TierOneLeverageCapitalRequiredToBeWellCapitalizedToAverageAssets_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Banking Regulation, Tier 1 Leverage Capital Ratio, Well Capitalized, Minimum</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_TierOneLeverageCapitalRequiredToBeWellCapitalizedToAverageAssets_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Tier 1 leverage (to average assets), To Be Well Capitalized</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_NumberOfForwardStartingContractsTerminated_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Number of forward starting contracts terminated</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_NumberOfForwardStartingContractsTerminated_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Number of forward starting contracts terminated.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_InvestmentsInDebtAndMarketableEquitySecuritiesAndCertainTradingAssetsDisclosureTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Investments in Debt and Marketable Equity Securities (and Certain Trading Assets) Disclosure [Text Block]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_InvestmentsInDebtAndMarketableEquitySecuritiesAndCertainTradingAssetsDisclosureTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Investment Securities</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AllOtherSegmentsMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Other Operating Segment [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AllOtherSegmentsMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Other Segments [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ScheduleOfFairValueOffBalanceSheetRisksTable_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Fair Value, off-Balance-Sheet Risk [Table]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ScheduleOfFairValueOffBalanceSheetRisksTable_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Schedule Of Fair Value Off Balance Sheet Risks [Table]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DefinedContributionPlanEmployerMatchingContributionPercentOfMatch_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Defined Contribution Plan, Employer Matching Contribution, Percent of Match</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DefinedContributionPlanEmployerMatchingContributionPercentOfMatch_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Defined Contribution Plan, Employer Matching Contribution, Percent of Match</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DerivativeMaturityDates_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Derivative, Contract End Date</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DerivativeMaturityDates_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Derivative, maturity dates</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DerivativeMaturityDates_lbl" xlink:role="http://www.xbrl.org/2003/role/verboseLabel">Derivative, contract end date</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DeferredFederalIncomeTaxExpenseBenefit_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Deferred Federal Income Tax Expense (Benefit)</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DeferredFederalIncomeTaxExpenseBenefit_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Federal</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_StockIssuedDuringPeriodValueShareBasedCompensation_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Shares Issued, Value, Share-Based Payment Arrangement, after Forfeiture</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_StockIssuedDuringPeriodValueShareBasedCompensation_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Impact of stock-based compensation plans, net</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_StockIssuedDuringPeriodValueShareBasedCompensation_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Shares Issued, Value, Share-Based Payment Arrangement, after Forfeiture, Total</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_RestructuringCostAndReserveLineItems_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Restructuring Cost and Reserve [Line Items]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_RestructuringCostAndReserveLineItems_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Restructuring Cost And Reserve [Line Items]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_UnrealizedGainLossOnInvestmentsTableTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Unrealized Gain (Loss) on Investments [Table Text Block]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_UnrealizedGainLossOnInvestmentsTableTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Schedule of Unrealized Loss and Fair Value on Investments for Securities for Which Allowance for Credit Losses has not been Recorded</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AociLossCashFlowHedgeCumulativeGainLossAfterTax_lbl" xlink:role="http://www.xbrl.org/2003/role/label">AOCI, Cash Flow Hedge, Cumulative Gain (Loss), after Tax</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AociLossCashFlowHedgeCumulativeGainLossAfterTax_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Cash flow hedge, cumulative gain (loss), after tax</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FinancialAssetAcquiredWithCreditDeteriorationMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Financial Asset Acquired with Credit Deterioration [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FinancialAssetAcquiredWithCreditDeteriorationMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Financial Asset Acquired With Credit Deterioration [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ComponentsOfDeferredTaxAssetsAbstract_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Components of Deferred Tax Assets [Abstract]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ComponentsOfDeferredTaxAssetsAbstract_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Deferred tax assets:</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_InvestmentIntoCapitalSurplus_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Investment into capital surplus.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_InvestmentIntoCapitalSurplus_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Investment Into Capital Surplus</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_InvestmentIntoCapitalSurplus_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Investment into capital surplus</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_OtherLiabilities_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Other Liabilities</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_OtherLiabilities_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Other liabilities</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_OtherLiabilities_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Other Liabilities, Total</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FederalReserveBankAdvancesMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Federal Reserve Bank Advances [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FederalReserveBankAdvancesMember_lbl" xlink:role="http://www.xbrl.org/2003/role/verboseLabel">FRB [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FederalReserveBankAdvancesMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Federal Reserve Bank Advances [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_OtherRealEstateAssetsAcquiredInRepossessionsTableTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Other real estate assets acquired in repossessions.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_OtherRealEstateAssetsAcquiredInRepossessionsTableTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Other Real Estate Assets Acquired In Repossessions Table [Text Block]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_OtherRealEstateAssetsAcquiredInRepossessionsTableTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Summary of Repossessed Assets Activity</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FairValueDisclosuresAbstract_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Fair Value Disclosures [Abstract]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_CommitmentsAndContingenciesDisclosureAbstract_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Commitments and Contingencies Disclosure [Abstract]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_ProceedsFromSaleOfPremisesAndEquipmentAndOtherRealEstate_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Proceeds from sale of premises and equipment and other real estate.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_ProceedsFromSaleOfPremisesAndEquipmentAndOtherRealEstate_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Proceeds From Sale Of Premises And Equipment And Other Real Estate</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_ProceedsFromSaleOfPremisesAndEquipmentAndOtherRealEstate_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Proceeds from the sale of premises and equipment and other real estate</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_InterestRateSwapsRelatedToInterestBearingLiabilitiesMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Interest Rate Swaps Related to Interest-Bearing Liabilities [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_InterestRateSwapsRelatedToInterestBearingLiabilitiesMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Interest Rate Swaps Related to Interest-Bearing Liabilities [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_InterestRateSwapsRelatedToInterestBearingLiabilitiesMember_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Interest rate swaps related to interest-bearing liabilities member.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_OrganizationConsolidationAndPresentationOfFinancialStatementsTable_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Organization consolidation and presentation of financial statements.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_OrganizationConsolidationAndPresentationOfFinancialStatementsTable_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Organization Consolidation And Presentation Of Financial Statements [Table]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_OrganizationConsolidationAndPresentationOfFinancialStatementsTable_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Organization Consolidation And Presentation Of Financial Statements [Table]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueNextTwelveMonths_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">2026</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueNextTwelveMonths_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Lessee, Operating Lease, Liability, to be Paid, Year One</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_CommercialAndIndustrialLoansMember_lbl" xlink:role="http://www.xbrl.org/2003/role/verboseLabel">Commercial And Industrial Loans [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_CommercialAndIndustrialLoansMember_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Represents information pertaining to commercial and industrial loans.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_CommercialAndIndustrialLoansMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Commercial And Industrial Loans [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_CommercialAndIndustrialLoansMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Commercial and Industrial Loans [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_ScheduleOfDerivativeInstrumentsEffectOnStatementOfOperationsTableTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Schedule of derivative instruments effect on statement of operations.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_ScheduleOfDerivativeInstrumentsEffectOnStatementOfOperationsTableTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Schedule Of Derivative Instruments Effect On Statement Of Operations Table [Text Block]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_ScheduleOfDerivativeInstrumentsEffectOnStatementOfOperationsTableTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Schedule of Hedging Derivative Instruments' Effect on Company's Consolidated Statement of Operations</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LineOfCredit_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Line of credit agreement with related party expired</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LineOfCredit_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Long-Term Line of Credit</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LineOfCredit_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Long-Term Line of Credit, Total</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_NumberOfCreditRiskParticipationAgreement_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Number of credit risk participation agreement</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_NumberOfCreditRiskParticipationAgreement_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Number Of Credit Risk Participation Agreement</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_NumberOfCreditRiskParticipationAgreement_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Number of credit risk participation agreement.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DerivativeInstrumentRiskAxis_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Derivative Instrument [Axis]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DerivativeInstrumentRiskAxis_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Derivative Instrument</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_MortgageLoansOnRealEstateForeclosures_lbl" xlink:role="http://www.xbrl.org/2003/role/label">SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate, Foreclosure</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_MortgageLoansOnRealEstateForeclosures_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Assets acquired in settlement of loans</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueAfterYearFive_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Lessee, Operating Lease, Liability, to be Paid, after Year Five</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueAfterYearFive_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">2030 and thereafter</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DisclosureOfCompensationRelatedCostsSharebasedPaymentsAbstract_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Share-Based Payment Arrangement [Abstract]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DepositLiabilitiesDisclosuresTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Deposit Liabilities Disclosures [Text Block]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DepositLiabilitiesDisclosuresTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Deposits</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DeferredTaxLiabilitiesGoodwillAndIntangibleAssetsIntangibleAssets_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Deferred Tax Liabilities, Intangible Assets</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DeferredTaxLiabilitiesGoodwillAndIntangibleAssetsIntangibleAssets_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Core deposit intangible</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_SubsidiarySaleOfStockAxis_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Sale of Stock [Axis]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_SubsidiarySaleOfStockAxis_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Sale of Stock</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DerivativesPolicyTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Derivatives, Policy [Policy Text Block]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DerivativesPolicyTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Derivatives and Hedging Activities</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_IncomeLossBeforeEquityInUndistributedIncomeOfSubsidiaries_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Income loss before equity in undistributed income of subsidiaries.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_IncomeLossBeforeEquityInUndistributedIncomeOfSubsidiaries_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Income Loss Before Equity In Undistributed Income Of Subsidiaries</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_IncomeLossBeforeEquityInUndistributedIncomeOfSubsidiaries_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Gain before equity in undistributed income of subsidiaries</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_NetCashProvidedByUsedInInvestingActivities_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Cash Provided by (Used in) Investing Activity, Including Discontinued Operation</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_NetCashProvidedByUsedInInvestingActivities_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Net cash used in investing activities</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_PrivatePlacementMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Private Placement [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_PrivatePlacementMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Private Placement [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_RestructuringAndRelatedCostNumberOfOfficeClosed_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Number of office closed</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_RestructuringAndRelatedCostNumberOfOfficeClosed_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Represents number of office closed during period for restructuring and related cost.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_RestructuringAndRelatedCostNumberOfOfficeClosed_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Restructuring And Related Cost Number Of Office Closed</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_PassMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Pass [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_PassMember_lbl" xlink:role="http://www.xbrl.org/2003/role/verboseLabel">Pass</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_PassMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Pass [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_CollateralLoansIndividuallyEvaluatedAmortizedCostBasis_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Total loans individually evaluated</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_CollateralLoansIndividuallyEvaluatedAmortizedCostBasis_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Collateral Loans Individually Evaluated Amortized Cost Basis</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_CollateralLoansIndividuallyEvaluatedAmortizedCostBasis_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Collateral Loans Individually Evaluated Amortized Cost Basis</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="dei_Security12bTitle_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Title of 12(b) Security</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="dei_Security12bTitle_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Title of 12(b) Security</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_CommonEquityTierOneRiskBasedCapitalRequiredForCapitalAdequacyToRiskWeightedAssets_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Common equity tier one risk based capital required for capital adequacy to risk weighted assets.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_CommonEquityTierOneRiskBasedCapitalRequiredForCapitalAdequacyToRiskWeightedAssets_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Common Equity Tier One Risk Based Capital Required For Capital Adequacy To Risk Weighted Assets</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_CommonEquityTierOneRiskBasedCapitalRequiredForCapitalAdequacyToRiskWeightedAssets_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Common equity Tier 1 capital (to risk-weighted assets), Minimum Requirement</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DerivativeInstrumentsAndHedgingActivitiesDisclosureTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Derivative Instruments and Hedging Activities Disclosure [Text Block]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DerivativeInstrumentsAndHedgingActivitiesDisclosureTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Derivative Financial Instruments</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_IncomeTaxPaidByIndividualJurisdictionTable_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Income Tax Paid, by Individual Jurisdiction [Table]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DefinedBenefitPlanNumberOfSharesOfEquitySecuritiesIssuedByEmployerAndRelatedPartiesIncludedInPlanAssets_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Defined Benefit Plan, Plan Assets, Employer, Related Party, Number of Shares</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DefinedBenefitPlanNumberOfSharesOfEquitySecuritiesIssuedByEmployerAndRelatedPartiesIncludedInPlanAssets_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Defined Benefit Plan, Plan Assets, Employer, Related Party, Number of Shares</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsForfeituresInPeriodWeightedAverageExercisePrice_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Share-Based Compensation Arrangements by Share-Based Payment Award, Options, Forfeitures in Period, Weighted Average Exercise Price</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsForfeituresInPeriodWeightedAverageExercisePrice_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Forfeited, weighted average exercise price (in dollars per share)</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeituresWeightedAverageGrantDateFairValue_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Forfeitures, Weighted Average Grant Date Fair Value</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeituresWeightedAverageGrantDateFairValue_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Forfeited, weighted-average grant-date fair value (in dollars per share)</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AvailableForSaleSecuritiesDebtMaturitiesAfterOneThroughFiveYearsAmortizedCost_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Debt Securities, Available-for-Sale, Amortized Cost, Maturity, Allocated and Single Maturity Date, after Year One Through Five</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AvailableForSaleSecuritiesDebtMaturitiesAfterOneThroughFiveYearsAmortizedCost_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Available-for-sale, maturing after one to five years, amortized cost</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_RelatedPartyDomain_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Related and Nonrelated Parties [Domain]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_IncomeTaxDisclosureTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Income Tax Disclosure [Text Block]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_IncomeTaxDisclosureTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Income Taxes</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DebtSecuritiesAvailableForSaleAllowanceForCreditLoss_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Debt Securities, Available-for-Sale, Allowance for Credit Loss</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DebtSecuritiesAvailableForSaleAllowanceForCreditLoss_lbl" xlink:role="http://www.xbrl.org/2003/role/periodEndLabel">Debt Securities, Available-for-Sale, Allowance for Credit Loss, Ending Balance</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DebtSecuritiesAvailableForSaleAllowanceForCreditLoss_lbl" xlink:role="http://www.xbrl.org/2003/role/periodStartLabel">Debt Securities, Available-for-Sale, Allowance for Credit Loss, Beginning Balance</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DebtSecuritiesAvailableForSaleAllowanceForCreditLoss_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Debt Securities, Available-for-Sale, Allowance for Credit Loss, Total</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DebtSecuritiesAvailableForSaleAllowanceForCreditLoss_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Available for sale, allowance for credit losses</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DebtSecuritiesAvailableForSaleAllowanceForCreditLoss_lbl" xlink:role="http://www.xbrl.org/2003/role/verboseLabel">Available-for-sale securities allowance for credit loss</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_IncomeStatementLineItems_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Income Statement [Line Items]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_IncomeStatementLineItems_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Income Statement.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_ForwardInterestRateSwapContractsTwoMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Forward Interest Rate Swap Contracts Two [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_ForwardInterestRateSwapContractsTwoMember_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Forward interest rate swap contracts two.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_ForwardInterestRateSwapContractsTwoMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Forward Interest Rate Swap Contracts Two [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_NumberOfFullTimeEmploymentPositionsEliminated_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Number of full time employment positions eliminated.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_NumberOfFullTimeEmploymentPositionsEliminated_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Number Of Full Time Employment Positions Eliminated</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_NumberOfFullTimeEmploymentPositionsEliminated_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Number of full-time employment positions eliminated</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_InterestExpenseShortTermBorrowings_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Interest Expense, Short-Term Borrowings</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_InterestExpenseShortTermBorrowings_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Interest Expense, Short-Term Borrowings, Total</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_InterestExpenseShortTermBorrowings_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Interest on borrowings</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="dei_LegalEntityAxis_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Legal Entity [Axis]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="dei_LegalEntityAxis_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Legal Entity</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AvailableForSaleSecuritiesDebtMaturitiesAfterOneThroughFiveYearsFairValue_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Debt Securities, Available-for-Sale, Fair Value, Maturity, Allocated and Single Maturity Date, after Year One Through Five</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AvailableForSaleSecuritiesDebtMaturitiesAfterOneThroughFiveYearsFairValue_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Available-for-sale, maturing after one to five years, estimated fair value</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ReconciliationOfRevenueFromSegmentsToConsolidatedTable_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Reconciliation of Revenue from Segments to Consolidated [Table]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ReconciliationOfRevenueFromSegmentsToConsolidatedTable_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Reconciliation Of Revenue From Segments To Consolidated [Table]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_IncreaseDecreaseInOperatingCapitalAbstract_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Adjustment to Reconcile Net Income to Cash Provided by (Used in) Operating Activity, Increase (Decrease) in Operating Capital [Abstract]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_IncreaseDecreaseInOperatingCapitalAbstract_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Changes in assets and liabilities:</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_StatementOfCashFlowsLineItems_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Statement Of Cash Flows [Line Items]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_StatementOfCashFlowsLineItems_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Statement of cash flows.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_PropertyPlantAndEquipmentTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Property, Plant and Equipment [Table Text Block]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_PropertyPlantAndEquipmentTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Premises and Equipment</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_PercentageOfLoansAndLeasesPastDue_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Percentage of loans and leases past due.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_PercentageOfLoansAndLeasesPastDue_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Percentage Of Loans And Leases Past Due</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_PercentageOfLoansAndLeasesPastDue_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">As a percentage of total loans, Total Past Due</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Outstanding, Weighted Average Exercise Price</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice_lbl" xlink:role="http://www.xbrl.org/2003/role/periodStartLabel">Outstanding, beginning of year, weighted average exercise price (in dollars per share)</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice_lbl" xlink:role="http://www.xbrl.org/2003/role/periodEndLabel">Options outstanding, end of year, weighted average exercise price (in dollars per share)</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_HeldToMaturitySecuritiesDebtMaturitiesAfterOneThroughFiveYearsFairValue_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Debt Securities, Held-to-Maturity, Fair Value, Maturity, Allocated and Single Maturity Date, after Year One Through Five</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_HeldToMaturitySecuritiesDebtMaturitiesAfterOneThroughFiveYearsFairValue_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Held-to-maturity, maturing after one to five years, estimated fair value</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_InterestAndDividendIncomeSecuritiesOther_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Interest and Dividend Income, Securities, Operating, Other</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_InterestAndDividendIncomeSecuritiesOther_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Other interest and dividends</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_TimeDeposits_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Time Deposits</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_TimeDeposits_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Total</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_TimeDepositMaturitiesYearThree_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Time Deposit Maturities, Year Three</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_TimeDepositMaturitiesYearThree_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">2027</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_IncomeTaxDisclosureAbstract_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Income Tax Disclosure [Abstract]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_TierOneLeverageCapitalRequiredForCapitalAdequacyToAverageAssets_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Banking Regulation, Tier 1 Leverage Capital Ratio, Capital Adequacy, Minimum</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_TierOneLeverageCapitalRequiredForCapitalAdequacyToAverageAssets_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Tier 1 leverage (to average assets), Minimum Requirement</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_OtherForeclosedAssets_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Other Repossessed Assets</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_OtherForeclosedAssets_lbl" xlink:role="http://www.xbrl.org/2003/role/periodEndLabel">Ending balance</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_OtherForeclosedAssets_lbl" xlink:role="http://www.xbrl.org/2003/role/periodStartLabel">Beginning balance</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_OtherForeclosedAssets_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Repossessed assets</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Fair Value, Recurring and Nonrecurring [Table]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Table]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_OmnibusIncentivePlanMember_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">The omnibus incentive plan.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_OmnibusIncentivePlanMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Omnibus Incentive Plan [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_OmnibusIncentivePlanMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Omnibus Incentive Plan [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_UnrecognizedTaxBenefits_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Unrecognized Tax Benefits</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_UnrecognizedTaxBenefits_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Unrecognized Tax Benefits, Ending Balance</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_UnrecognizedTaxBenefits_lbl" xlink:role="http://www.xbrl.org/2003/role/periodStartLabel">Unrecognized Tax Benefits, Beginning Balance</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_UnrecognizedTaxBenefits_lbl" xlink:role="http://www.xbrl.org/2003/role/periodEndLabel">Unrecognized Tax Benefits, Ending Balance</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AdditionalPaidInCapitalMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Additional Paid-in Capital [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AdditionalPaidInCapitalMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Additional Paid-in Capital [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_CapitalToRiskWeightedAssets_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Banking Regulation, Total Risk-Based Capital Ratio, Actual</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_CapitalToRiskWeightedAssets_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Total capital (to risk-weighted assets), Actual Regulatory Capital, Ratio</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_CommercialMortgageBackedSecuritiesMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Commercial Mortgage-Backed Securities [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_CommercialMortgageBackedSecuritiesMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Commercial Mortgage Backed Securities [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_LongTermDebtAverageRatePaidIncludingAmortizationOfDebtIssuanceCosts_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Long term debt average rate paid including amortization of debt issuance costs.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_LongTermDebtAverageRatePaidIncludingAmortizationOfDebtIssuanceCosts_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Long Term Debt Average Rate Paid Including Amortization Of Debt Issuance Costs</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_LongTermDebtAverageRatePaidIncludingAmortizationOfDebtIssuanceCosts_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Average rate paid during the year, including amortization of debt issuance costs</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_HeldToMaturitySecuritiesDebtMaturitiesAfterFiveThroughTenYearsFairValue_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Debt Securities, Held-to-Maturity, Fair Value, Maturity, Allocated and Single Maturity Date, after Year 5 Through 10</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_HeldToMaturitySecuritiesDebtMaturitiesAfterFiveThroughTenYearsFairValue_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Held-to-maturity, maturity after five to ten years, estimated fair value</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FairValueMeasurementFrequencyDomain_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Measurement Frequency [Domain]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FairValueMeasurementFrequencyDomain_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Measurement Frequency</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_GeneralInsuranceExpense_lbl" xlink:role="http://www.xbrl.org/2003/role/verboseLabel">Insurance expense and assessments</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_GeneralInsuranceExpense_lbl" xlink:role="http://www.xbrl.org/2003/role/label">General Insurance Expense</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_GeneralInsuranceExpense_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Insurance expense</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_IncomeStatementLocationAxis_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Statement of Income Location, Balance [Axis]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_IncomeStatementLocationAxis_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Income Statement Location</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="dei_TradingSymbol_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Trading Symbol</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="dei_TradingSymbol_lbl" xlink:role="http://www.xbrl.org/2003/role/verboseLabel">Trading Symbol</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ScheduleOfFiniteLivedIntangibleAssetsTable_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Intangible Asset, Finite-Lived [Table]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ScheduleOfFiniteLivedIntangibleAssetsTable_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Schedule Of Finite Lived Intangible Assets [Table]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_PropertyPlantAndEquipmentDisclosureTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Property, Plant and Equipment Disclosure [Text Block]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_PropertyPlantAndEquipmentDisclosureTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Premises and Equipment</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_OpenTaxYear_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Open Tax Year</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_OpenTaxYear_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Open Tax Year</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AvailableForSaleSecuritiesDebtMaturitiesWithinOneYearAmortizedCost_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Debt Securities, Available-for-Sale, Amortized Cost, Maturity, Allocated and Single Maturity Date, Year One</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AvailableForSaleSecuritiesDebtMaturitiesWithinOneYearAmortizedCost_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Available-for-sale, maturing within one year, amortized cost</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_EffectiveIncomeTaxRateReconciliationNondeductibleExpense_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Effective Income Tax Rate Reconciliation, Nondeductible Expense, Percent</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_EffectiveIncomeTaxRateReconciliationNondeductibleExpense_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Effective Income Tax Rate Reconciliation, Nondeductible Expense, Percent, Total</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_EffectiveIncomeTaxRateReconciliationNondeductibleExpense_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Nontaxable or nondeductible items</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_TierOneRiskBasedCapitalRequiredToBeWellCapitalizedToRiskWeightedAssets_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Banking Regulation, Tier 1 Risk-Based Capital Ratio, Well Capitalized, Minimum</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_TierOneRiskBasedCapitalRequiredToBeWellCapitalizedToRiskWeightedAssets_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Tier 1 capital (to risk-weighted assets), To Be Well Capitalized</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_SubsequentEventTypeAxis_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Subsequent Event Type [Axis]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_CreditQualityInformationAbstract_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Credit Quality Information [Abstract]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_MortgageLoansInProcessOfForeclosureAmount_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Mortgage Loans in Process of Foreclosure, Amount</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_MortgageLoansInProcessOfForeclosureAmount_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Mortgage loans in process of foreclosure, amount</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_OtherComprehensiveIncomeLossCashFlowHedgeGainLossBeforeReclassificationTax_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), before Reclassification, Tax</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_OtherComprehensiveIncomeLossCashFlowHedgeGainLossBeforeReclassificationTax_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Unrealized holding (losses) gains on effective cash flow hedge derivatives arising during the year, tax (expense) benefit</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_IncomeTaxReconciliationTaxExemptIncome_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Effective Income Tax Rate Reconciliation, Tax Exempt Income, Amount</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_IncomeTaxReconciliationTaxExemptIncome_lbl" xlink:role="http://www.xbrl.org/2009/role/negatedLabel">Tax-exempt interest</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AllowanceForCreditLossesOnFinancingReceivablesTableTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Financing Receivable, Allowance for Credit Loss [Table Text Block]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AllowanceForCreditLossesOnFinancingReceivablesTableTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Allowance for Credit Losses on Loans and Leases</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Cash Provided by (Used in) Financing Activity, Including Discontinued Operation [Abstract]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Cash flows from financing activities:</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_FixedAssetValuationAdjustments_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Fixed asset valuation adjustments.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_FixedAssetValuationAdjustments_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Fixed Asset Valuation Adjustments</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_FixedAssetValuationAdjustments_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Fixed asset valuation adjustments</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FairValueMeasurementsRecurringMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Fair Value, Recurring [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FairValueMeasurementsRecurringMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Fair Value, Recurring [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LesseeOperatingLeaseLiabilityPaymentsDue_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Lessee, Operating Lease, Liability, to be Paid</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LesseeOperatingLeaseLiabilityPaymentsDue_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Total future minimum lease payments</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_InterestRateSwapsRelatedToFixedRateCommercialRealEstateLoansMember_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Interest rate swaps related to fixed rate commercial real estate loans.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_InterestRateSwapsRelatedToFixedRateCommercialRealEstateLoansMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Interest Rate Swaps Related To Fixed Rate Commercial Real Estate Loans [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_InterestRateSwapsRelatedToFixedRateCommercialRealEstateLoansMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Interest Rate Swaps Related to Fixed Rate Commercial Real Estate Loans [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AccountingStandardsUpdate201613Member_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Impact of adopting ASC 326 [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AccountingStandardsUpdate201613Member_lbl" xlink:role="http://www.xbrl.org/2003/role/verboseLabel">Impact of Adopting CECL [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AccountingStandardsUpdate201613Member_lbl" xlink:role="http://www.xbrl.org/2003/role/label">ASC 326 [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_CumulativeBasisAdjustmentsAssociatedWithHedgingRelationships_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Cumulative basis adjustments associated with hedging relationships.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_CumulativeBasisAdjustmentsAssociatedWithHedgingRelationships_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Cumulative Basis Adjustments Associated With Hedging Relationships</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_CumulativeBasisAdjustmentsAssociatedWithHedgingRelationships_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Cumulative basis adjustments associated with hedging relationships</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LesseeOperatingLeaseLiabilityUndiscountedExcessAmount_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Lessee, Operating Lease, Liability, Undiscounted Excess Amount</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LesseeOperatingLeaseLiabilityUndiscountedExcessAmount_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Less: Imputed interest</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FinancingReceivablePortfolioSegmentDomain_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Financing Receivable Portfolio Segment [Domain]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FinancingReceivablePortfolioSegmentDomain_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Financing Receivable Portfolio Segment</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_RepossessionsPolicyTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Repossessions [Policy Text Block]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_RepossessionsPolicyTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Repossessions.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_RepossessionsPolicyTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Repossessions</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_DescriptionOfMaturityPeriod_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Description of Maturity Period</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_DescriptionOfMaturityPeriod_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Description of maturity period.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_DescriptionOfMaturityPeriod_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Maturities description</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_InterestAndDividendIncomeSecurities_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Interest and Dividend Income, Securities, Operating, Total</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_InterestAndDividendIncomeSecurities_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Interest and Dividend Income, Securities, Operating</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_InterestAndDividendIncomeSecurities_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Interest on investment securities</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FederalHomeLoanBankAdvancesGeneralDebtObligationsDisclosuresCollateralPledged1_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Federal Home Loan Bank, Advances, General Debt Obligations, Disclosures, Collateral Pledged</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FederalHomeLoanBankAdvancesGeneralDebtObligationsDisclosuresCollateralPledged1_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Federal Home Loan Bank, advances, general debt obligations, disclosures, collateral pledged</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_StatementEquityComponentsAxis_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Equity Components [Axis]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_StatementEquityComponentsAxis_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Equity Components</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_EquityComponentDomain_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Equity Component [Domain]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_EquityComponentDomain_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Equity Component</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_PerformingAndNonPerformingMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Performing And Non Performing [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_PerformingAndNonPerformingMember_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Performing And Non Performing [Member].</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_PerformingAndNonPerformingMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Performing And Non Performing [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_GoodwillAndIntangibleAssetsDisclosureAbstract_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Goodwill and Intangible Assets Disclosure [Abstract]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_StateAndLocalTaxJurisdictionOtherMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">State and Local Tax Jurisdiction, Other [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_StateAndLocalTaxJurisdictionOtherMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Other [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_OtherAssetsInterestRateFloorsMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Other Assets Interest Rate Floors [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_OtherAssetsInterestRateFloorsMember_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Other assets interest rate floors.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_OtherNoninterestExpense_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Other Noninterest Expense</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_OtherNoninterestExpense_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Other expense</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="dei_DocumentAnnualReport_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Document Annual Report</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="dei_DocumentAnnualReport_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Document Annual Report</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_InterestIncomeExpenseNetMember_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Interest income (expense) net.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_InterestIncomeExpenseNetMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Interest Income (Expense) Net [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_InterestIncomeExpenseNetMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Net Interest Income (Expense) [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_BankOwnedLifeInsurance_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Bank Owned Life Insurance</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_BankOwnedLifeInsurance_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Cash surrender value of bank-owned life insurance</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_BusinessAcquisitionAxis_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Business Combination [Axis]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_BusinessAcquisitionAxis_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Business Acquisition</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_OperatingLeaseLiabilityStatementOfFinancialPositionExtensibleList_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Operating Lease, Liability, Statement of Financial Position [Extensible Enumeration]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AvailableForSaleSecuritiesDebtMaturitiesAfterFiveThroughTenYearsAmortizedCost_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Debt Securities, Available-for-Sale, Amortized Cost, Maturity, Allocated and Single Maturity Date, after Year 5 Through 10</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AvailableForSaleSecuritiesDebtMaturitiesAfterFiveThroughTenYearsAmortizedCost_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Available-for-sale, maturing after five to ten years, amortized cost</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LeaseIncome_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Lease Income</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LeaseIncome_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Lease income</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LeaseIncome_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Lease Income, Total</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_BalanceSheetRelatedDisclosuresTable_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Balance Sheet Related Disclosures [Table]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_BalanceSheetRelatedDisclosuresTable_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Balance sheet related disclosures.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_OtherInterestAndDividendIncome_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Other</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_OtherInterestAndDividendIncome_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Other Interest and Dividend Income</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FederalHomeLoanBankAdvancesBranchOfFHLBBankAmountOfAdvancesByBranch_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Federal Home Loan Bank, Advance, Branch of FHLBank, Amount</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FederalHomeLoanBankAdvancesBranchOfFHLBBankAmountOfAdvancesByBranch_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Collateral exposure with FHLB in form of advances</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_SoftwareMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Software [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_SoftwareMember_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Software.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DepreciationAndAmortization_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Depreciation, Depletion and Amortization, Nonproduction</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DepreciationAndAmortization_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Depreciation expense</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DepreciationAndAmortization_lbl" xlink:role="http://www.xbrl.org/2003/role/verboseLabel">Depreciation and amortization expense</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DepreciationAndAmortization_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Depreciation, Depletion and Amortization, Nonproduction, Total</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_OtherRealEstateGrossGains_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Other real estate gross gains.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_OtherRealEstateGrossGains_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Other Real Estate Gross Gains</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_OtherRealEstateGrossGains_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Gross gains</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_NotesReceivableNet_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Financing Receivable, after Allowance for Credit Loss, Total</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_NotesReceivableNet_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Financing Receivable, after Allowance for Credit Loss</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_NotesReceivableNet_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Loans pledged as collateral</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_StatementOfIncomeAndComprehensiveIncomeAbstract_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Statement of Comprehensive Income [Abstract]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="srt_MaximumMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Maximum [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="srt_MaximumMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Maximum [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_PercentageOfAssets_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Percentage of total assets</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_PercentageOfAssets_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Percentage Of Assets</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_PercentageOfAssets_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Percentage of assets.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LiabilitiesFairValueDisclosure_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Liabilities, Fair Value Disclosure</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LiabilitiesFairValueDisclosure_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Financial and Nonfinancial Liabilities, Fair Value Disclosure</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LiabilitiesFairValueDisclosure_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Liabilities, Fair Value Disclosure, Total</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DesignatedAsHedgingInstrumentMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Designated as Hedging Instrument [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DesignatedAsHedgingInstrumentMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Derivatives Designated as Hedging Instruments [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LoansAndLeasesReceivableNetReportedAmount_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Net loans and leases held for investment</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LoansAndLeasesReceivableNetReportedAmount_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Net loans and leases held for investment</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LoansAndLeasesReceivableNetReportedAmount_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Loans and Leases Receivable, Net Amount</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LoansAndLeasesReceivableNetReportedAmount_lbl" xlink:role="http://www.xbrl.org/2003/role/verboseLabel">Loans net of unearned income and unamortized deferred fees and costs</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="srt_RangeAxis_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Statistical Measurement [Axis]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="srt_RangeAxis_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Statistical Measurement</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsExercisesInPeriodWeightedAverageExercisePrice_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Share-Based Compensation Arrangements by Share-Based Payment Award, Options, Exercises in Period, Weighted Average Exercise Price</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsExercisesInPeriodWeightedAverageExercisePrice_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Exercised, weighted average exercise price (in dollars per share)</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FiniteLivedIntangibleAssetsAccumulatedAmortization_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Finite-Lived Intangible Assets, Accumulated Amortization</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FiniteLivedIntangibleAssetsAccumulatedAmortization_lbl" xlink:role="http://www.xbrl.org/2009/role/negatedLabel">Accumulated amortization</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_TimeDepositMaturitiesYearOne_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Time Deposit Maturities, Year One</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_TimeDepositMaturitiesYearOne_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">2025</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_CommonStockValue_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Common Stock, Value, Issued</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_CommonStockValue_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Common stock, par value $0.01 per share, 10,000,000 shares authorized; 7,947,303 and 7,840,348 shares issued, respectively; 5,699,696 and 5,696,171 outstanding, respectively</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FederalFundsPurchased_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Federal Funds Purchased</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FederalFundsPurchased_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Federal Funds Purchased</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ScheduleOfFinancingReceivableAllowanceForCreditLossesTable_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Financing Receivable, Allowance for Credit Loss [Table]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ConsolidationPolicyTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Consolidation, Policy [Policy Text Block]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ConsolidationPolicyTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Principles of Consolidation</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_NumberOfSecuritiesHeldAsTradingSecurities_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Represents the number of securities held as trading securities.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_NumberOfSecuritiesHeldAsTradingSecurities_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Number Of Securities Held As Trading Securities</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_NumberOfSecuritiesHeldAsTradingSecurities_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Number of securities held as trading securities</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest_lbl" xlink:role="http://www.xbrl.org/2003/role/verboseLabel">Decrease to retained earnings</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Equity, Including Portion Attributable to Noncontrolling Interest</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest_lbl" xlink:role="http://www.xbrl.org/2003/role/periodEndLabel">Ending balance, value</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest_lbl" xlink:role="http://www.xbrl.org/2003/role/periodStartLabel">Beginning balance, value</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Shareholders&#8217; equity</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Total shareholders&#8217; equity</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_BankOwnedLifeInsuranceIncome_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Bank Owned Life Insurance Income</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_BankOwnedLifeInsuranceIncome_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Bank-owned life insurance</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="cyd_CybersecurityRiskManagementProcessesForAssessingIdentifyingAndManagingThreatsTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Cybersecurity Risk Management Processes for Assessing, Identifying, and Managing Threats [Text Block]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_ComputerServicesExpense_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Computer services expense</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_ComputerServicesExpense_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Computer Services Expense</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_ComputerServicesExpense_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Computer services</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_EffectiveIncomeTaxRateReconciliationStateAndLocalIncomeTaxes_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">State and local income taxes, net of federal income tax effect</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_EffectiveIncomeTaxRateReconciliationStateAndLocalIncomeTaxes_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Effective Income Tax Rate Reconciliation, State and Local Income Taxes, Percent</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ScheduleofFiniteLivedIntangibleAssetsFutureAmortizationExpenseTableTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Schedule of Finite-Lived Intangible Assets, Future Amortization Expense [Table Text Block]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ScheduleofFiniteLivedIntangibleAssetsFutureAmortizationExpenseTableTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Schedule of Estimated Remaining Amortization Expense</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_OtherIncomeATMFees_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Other income ATM fees.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_OtherIncomeATMFees_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Other Income A T M Fees</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_OtherIncomeATMFees_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">ATM fee income</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_TimeDepositsAtOrAboveFDICInsuranceLimit_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Time Deposits, at or Above FDIC Insurance Limit</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_TimeDepositsAtOrAboveFDICInsuranceLimit_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Time Deposits, at or Above FDIC Insurance Limit</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="dei_EntityPublicFloat_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Entity Public Float</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="dei_EntityPublicFloat_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Entity Public Float</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_IncomeTaxesPaidNetAbstract_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Income Taxes Paid, Net [Abstract]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_IncomeTaxesPaidNetAbstract_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Income taxes paid, net of refunds</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FairValueOffBalanceSheetRisksDisclosureInformationLineItems_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Fair Value, off-Balance-Sheet Risks, Disclosure Information [Line Items]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FairValueOffBalanceSheetRisksDisclosureInformationLineItems_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Fair Value Off Balance Sheet Risks Disclosure Information [Line Items]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Finite-Lived Intangible Assets by Major Class [Axis]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Finite-Lived Intangible Assets by Major Class</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_HeldToMaturitySecuritiesDebtMaturitiesAfterTenYearsFairValue_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Debt Securities, Held-to-Maturity, Fair Value, Maturity, Allocated and Single Maturity Date, after Year 10</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_HeldToMaturitySecuritiesDebtMaturitiesAfterTenYearsFairValue_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Held-to-maturity, maturing after ten years, estimated fair value</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_LoansHeldForInvestmentMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Loans held for investment [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_LoansHeldForInvestmentMember_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Loans held for investment.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_LoansHeldForInvestmentMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">LHFI [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_DerivativeInstrumentsGainLossReclassifiedFromAccumulatedOCIIntoIncomeEffectivePortionNet1_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Interest income (expense)</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_DerivativeInstrumentsGainLossReclassifiedFromAccumulatedOCIIntoIncomeEffectivePortionNet1_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Derivative Instruments, Gain (Loss) Reclassified from Accumulated OCI into Income, Effective Portion, Net1</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_DerivativeInstrumentsGainLossReclassifiedFromAccumulatedOCIIntoIncomeEffectivePortionNet1_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Derivative instruments, gain (loss) reclassified from accumulated OCI into income, effective portion, net.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_PaymentsRelatedToTaxWithholdingForShareBasedCompensation_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Payment, Tax Withholding, Share-Based Payment Arrangement</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_PaymentsRelatedToTaxWithholdingForShareBasedCompensation_lbl" xlink:role="http://www.xbrl.org/2009/role/negatedLabel">Net share-based compensation transactions</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_ScheduleOfDerivativeInstrumentsInStatementOfFinancialPositionNominalAmountAndFairValueTableTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Tabular disclosure of the location, nominal amount and fair value amounts of derivative instruments (and non-derivative instruments that are designated and qualify as hedging instruments) reported in the statement of financial position.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_ScheduleOfDerivativeInstrumentsInStatementOfFinancialPositionNominalAmountAndFairValueTableTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Schedule Of Derivative Instruments In Statement Of Financial Position Nominal Amount And Fair Value Table [Text Block]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_ScheduleOfDerivativeInstrumentsInStatementOfFinancialPositionNominalAmountAndFairValueTableTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Schedule of Notional Amount and Fair Value of Derivative Instruments Included on Company's Consolidated Balance Sheets on a net Basis</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_InterestBearingDepositLiabilities_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Interest-Bearing Deposit Liabilities</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_InterestBearingDepositLiabilities_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Interest-bearing</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_InterestBearingDepositLiabilities_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Interest-Bearing Deposit Liabilities, Total</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AccountsNotesAndLoansReceivableLineItems_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Accounts, Notes, Loans and Financing Receivable [Line Items]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FinancingReceivableAllowanceForCreditLossesIndividuallyEvaluatedForImpairment1_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Financing Receivable, Allowance for Credit Loss, Individually Evaluated</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FinancingReceivableAllowanceForCreditLossesIndividuallyEvaluatedForImpairment1_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Individually evaluated for impairment</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="dei_EntityRegistrantName_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Entity Registrant Name</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="dei_EntityRegistrantName_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Entity Registrant Name</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_UnrecognizedTaxBenefitsIncomeTaxPenaltiesAndInterestAccrued_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Unrecognized Tax Benefits, Income Tax Penalties and Interest Accrued</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_UnrecognizedTaxBenefitsIncomeTaxPenaltiesAndInterestAccrued_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Unrecognized Tax Benefits, Income Tax Penalties and Interest Accrued, Total</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_UnrecognizedTaxBenefitsIncomeTaxPenaltiesAndInterestAccrued_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Unrecognized Tax Benefits, Income Tax Penalties and Interest Accrued, Total</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedLossBeforeTax_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Debt Securities, Available-for-Sale, Accumulated Gross Unrealized Loss, before Tax</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedLossBeforeTax_lbl" xlink:role="http://www.xbrl.org/2009/role/negatedLabel">Available-for-sale, gross unrealized losses</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="dei_EntityVoluntaryFilers_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Entity Voluntary Filers</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="dei_EntityVoluntaryFilers_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Entity Voluntary Filers</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FederalHomeLoanBankAdvancesGeneralDebtObligationsDisclosuresDescriptionOfCollateralPledged_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Federal Home Loan Bank, Advances, General Debt Obligations, Disclosures, Description of Collateral Pledged</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FederalHomeLoanBankAdvancesGeneralDebtObligationsDisclosuresDescriptionOfCollateralPledged_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Collateral Requirements</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_TreasuryStockSharesAcquired_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Treasury Stock, Shares, Acquired</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_TreasuryStockSharesAcquired_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Shares repurchased</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_WeightedAverageDirectorDeferredShares_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Weighted average director deferred shares.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_WeightedAverageDirectorDeferredShares_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Weighted average director deferred shares</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_WeightedAverageDirectorDeferredShares_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Weighted average director deferred shares</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_IncreaseDecreaseInCashSurrenderValueOfBankOwnedLifeInsurance_lbl" xlink:role="http://www.xbrl.org/2009/role/negatedLabel">Increase in cash surrender value of bank owned life insurance</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_IncreaseDecreaseInCashSurrenderValueOfBankOwnedLifeInsurance_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Increase (decrease) in cash surrender value of bank owned life insurance</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_IncreaseDecreaseInCashSurrenderValueOfBankOwnedLifeInsurance_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Increase (decrease) in cash surrender value of bank owned life insurance.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DeferredStateAndLocalIncomeTaxExpenseBenefit_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Deferred State and Local Income Tax Expense (Benefit)</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DeferredStateAndLocalIncomeTaxExpenseBenefit_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">State</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_OtherAssetsInterestRateCapsMember_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Other assets interest rate caps.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_OtherAssetsInterestRateCapsMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Other Assets Interest Rate Caps [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="cyd_CybersecurityRiskManagementPositionsOrCommitteesResponsibleFlag_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Cybersecurity Risk Management Positions or Committees Responsible [Flag]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_SecuredOvernightFinancingRateSofrOvernightIndexSwapRateMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Secured Overnight Financing Rate (SOFR) Overnight Index Swap Rate [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_SecuredOvernightFinancingRateSofrOvernightIndexSwapRateMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Secured Overnight Financing Rate (SOFR) Overnight Index Swap Rate [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_IncomeTaxExpenseBenefit_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Income Tax Expense (Benefit)</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_IncomeTaxExpenseBenefit_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Provision for income taxes</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_IncomeTaxExpenseBenefit_lbl" xlink:role="http://www.xbrl.org/2003/role/verboseLabel">Provision for income taxes</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_IncomeTaxExpenseBenefit_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Total</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FairValueByMeasurementFrequencyAxis_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Measurement Frequency [Axis]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FairValueByMeasurementFrequencyAxis_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Measurement Frequency</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Share Based Compensation Arrangement By Share Based Payment Award [Line Items]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FederalHomeLoanBankAdvancesGeneralDebtObligationsDisclosuresAmountOfAvailableUnusedFunds_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Federal Home Loan Bank, Advances, General Debt Obligations, Amount of Available, Unused Funds</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FederalHomeLoanBankAdvancesGeneralDebtObligationsDisclosuresAmountOfAvailableUnusedFunds_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Available lines of credit</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_OtherAssetsInterestRateSwapsMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Other Assets interest Rate Swaps[Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_OtherAssetsInterestRateSwapsMember_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Other assets interest rate swaps.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_OtherAssetsInterestRateSwapsMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Other Assets Interest Rate Swaps [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsReleasedFromRestrictionInPeriodWeightedAverageGrantDateFairValue_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Share based compensation arrangement by share based payment award equity instruments other than options released from restriction in period weighted average grant date fair value</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsReleasedFromRestrictionInPeriodWeightedAverageGrantDateFairValue_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Share-based compensation arrangement by share-based payment award equity instruments other than options released from restriction in period weighted average grant date fair value.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsReleasedFromRestrictionInPeriodWeightedAverageGrantDateFairValue_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Released from restriction, weighted-average grant-date fair value (in dollars per share)</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="dei_EntityCommonStockSharesOutstanding_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Entity Common Stock, Shares Outstanding</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="dei_EntityCommonStockSharesOutstanding_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Entity Common Stock, Shares Outstanding</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_FinancingReceivableAllowanceForCreditLossWriteoffAfterRecoveryTable_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Financing Receivable, Allowance for Credit Loss, Writeoff, after Recovery [Table]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_FinancingReceivableAllowanceForCreditLossWriteoffAfterRecoveryTable_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Financing receivable, allowance for credit loss, writeoff, after recovery table.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_USStatesAndPoliticalSubdivisionsMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">US States and Political Subdivisions Debt Securities [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_USStatesAndPoliticalSubdivisionsMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">US States and Political Subdivisions Debt Securities [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FairValueByLiabilityClassAxis_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Liability Class [Axis]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Accumulated Other Comprehensive Income (Loss), Net of Tax</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Accumulated other comprehensive loss, net of tax</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Accumulated Other Comprehensive Income (Loss), Net of Tax, Total</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="srt_ConsolidationItemsAxis_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Consolidation Items [Axis]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="srt_ConsolidationItemsAxis_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Operating Segments [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AllowanceForDoubtfulAccountsReceivableWriteOffs_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Accounts Receivable, Allowance for Credit Loss, Writeoff</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AllowanceForDoubtfulAccountsReceivableWriteOffs_lbl" xlink:role="http://www.xbrl.org/2009/role/negatedLabel">Charge-offs</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_PaymentsToAcquirePropertyPlantAndEquipment_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Payments to Acquire Property, Plant, and Equipment</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_PaymentsToAcquirePropertyPlantAndEquipment_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Fixed asset additions</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_PaymentsToAcquirePropertyPlantAndEquipment_lbl" xlink:role="http://www.xbrl.org/2009/role/negatedLabel">Purchases of premises and equipment</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_PaymentsToAcquirePropertyPlantAndEquipment_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Payments to Acquire Property, Plant, and Equipment, Total</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Grants in Period</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Share-based compensation arrangement by share-based payment award, equity instruments other than options, grants in period</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod_lbl" xlink:role="http://www.xbrl.org/2003/role/verboseLabel">Granted (in shares)</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DepositLiabilitiesAccruedInterest_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Deposit Liabilities, Accrued Interest</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DepositLiabilitiesAccruedInterest_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Accrued interest expense</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_Assets_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Assets</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_Assets_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Total assets</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_Assets_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Total assets</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ScheduleOfPropertyPlantAndEquipmentTable_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Property, Plant and Equipment [Table]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ScheduleOfPropertyPlantAndEquipmentTable_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Schedule Of Property Plant And Equipment [Table]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_IncomeTaxPaidStateAndLocalAfterRefundReceived_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Income Tax Paid, State and Local, after Refund Received</link:label>
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          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_IncomeTaxPaidStateAndLocalAfterRefundReceived_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">State</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_PerformingFinancingReceivableMember_lbl" xlink:role="http://www.xbrl.org/2003/role/verboseLabel">Performing [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_PerformingFinancingReceivableMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Performing Financial Instruments [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_PerformingFinancingReceivableMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Performing Financial Instruments</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Class of Financing Receivable [Domain]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Class of Financing Receivable</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_IncomeStatementAbstract_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Income Statement [Abstract]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FinancingReceivableRecordedInvestmentPastDueLineItems_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Financing Receivable, Past Due [Line Items]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DerivativeAmountOfHedgedItem_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Derivative, Amount of Hedged Item</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DerivativeAmountOfHedgedItem_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Designated hedged items</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ScheduleOfRestructuringAndRelatedCostsTable_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Restructuring Cost [Table]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ScheduleOfRestructuringAndRelatedCostsTable_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Schedule Of Restructuring And Related Costs [Table]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_InterestRateCapMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Interest Rate Cap [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_InterestRateCapMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Interest Rate Cap [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DebtSecuritiesHeldtomaturityAllowanceForCreditLossLineItems_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Debt Securities, Held-to-Maturity, Allowance for Credit Loss [Line Items]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DebtSecuritiesHeldtomaturityAllowanceForCreditLossLineItems_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Debt Securities Heldtomaturity Allowance For Credit Loss [Line Items]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ShareBasedCompensationOptionAndIncentivePlansPolicy_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Share-Based Payment Arrangement [Policy Text Block]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ShareBasedCompensationOptionAndIncentivePlansPolicy_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Stock Based Compensation</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DeferredIncomeTaxExpenseBenefit_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Deferred Income Tax Expense (Benefit)</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DeferredIncomeTaxExpenseBenefit_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Deferred income tax expense</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DeferredIncomeTaxExpenseBenefit_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Total deferred</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="srt_WeightedAverageMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Weighted Average [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="srt_WeightedAverageMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Weighted Average [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_OtherRealEstateAssetsAcquiredInForeclosureRollForwardTableTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Other real estate assets acquired in foreclosure roll forward.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_OtherRealEstateAssetsAcquiredInForeclosureRollForwardTableTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Other Real Estate Assets Acquired In Foreclosure Roll Forward Table [Text Block]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_OtherRealEstateAssetsAcquiredInForeclosureRollForwardTableTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Summary of Foreclosed Property Activity</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_NetIncreaseDecreaseToIncomeBeforeIncomeTaxesMember_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Net increase decrease to income before income taxes.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_NetIncreaseDecreaseToIncomeBeforeIncomeTaxesMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Net Increase Decrease To Income Before Income Taxes [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_NetIncreaseDecreaseToIncomeBeforeIncomeTaxesMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Net Increase to Income Before Income Taxes [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_EarningsPerShareDiluted_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Earnings Per Share, Diluted</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_EarningsPerShareDiluted_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Diluted net income per share</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_EarningsPerShareDiluted_lbl" xlink:role="http://www.xbrl.org/2003/role/verboseLabel">Diluted earnings</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_EarningsPerShareDiluted_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Earnings Per Share, Diluted, Total</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_LoansNetOfUnamortizedPremiums_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Loans net of unamortized premiums</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_LoansNetOfUnamortizedPremiums_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Loans net of unamortized premiums.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Financing Receivable, Nonaccrual</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Non-accruing loans</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ScheduleOfSegmentReportingInformationBySegmentTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Schedule of Segment Reporting Information, by Segment [Table Text Block]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ScheduleOfSegmentReportingInformationBySegmentTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Summary of Information Related To The Company's Bank Operating Segment</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_OperatingSegmentsMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Operating Segments [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_OperatingSegmentsMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Operating Segments [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_PPPLoansMember_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">PPP loans member</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_PPPLoansMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">P P P Loans [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_PPPLoansMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">PPP Loans [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_EffectiveIncomeTaxRateContinuingOperationsTaxRateReconciliationAbstract_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Effective Income Tax Rate Reconciliation, Percent [Abstract]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_EffectiveIncomeTaxRateContinuingOperationsTaxRateReconciliationAbstract_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Percent</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="srt_TitleOfIndividualWithRelationshipToEntityDomain_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Title and Position [Domain]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="srt_TitleOfIndividualWithRelationshipToEntityDomain_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Title of Individual</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DividendsCommonStock_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Dividends, Common Stock</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DividendsCommonStock_lbl" xlink:role="http://www.xbrl.org/2003/role/verboseLabel">Dividends, Common Stock, Total</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DividendsCommonStock_lbl" xlink:role="http://www.xbrl.org/2009/role/negatedLabel">Dividends declared</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DividendsCommonStock_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Dividends, Common Stock, Total</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_InterestOnShortTermBorrowingsMember_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Interest on short-term borrowings member.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_InterestOnShortTermBorrowingsMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Interest On Short Term Borrowings [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_InterestOnShortTermBorrowingsMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Interest on Short-Term Borrowings [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="dei_CityAreaCode_lbl" xlink:role="http://www.xbrl.org/2003/role/label">City Area Code</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="dei_CityAreaCode_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">City Area Code</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_WeightedAverageNumberOfSharesOutstanding_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Weighted average number of shares outstanding.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_WeightedAverageNumberOfSharesOutstanding_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Weighted Average Number of Shares Outstanding</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_WeightedAverageNumberOfSharesOutstanding_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Weighted average shares outstanding</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_OtherComprehensiveIncomeLossNetOfTax_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Other Comprehensive Income (Loss), Net of Tax</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_OtherComprehensiveIncomeLossNetOfTax_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Other comprehensive income</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ProvisionForLoanLossesExpensed_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Financing Receivable, Credit Loss, Expense (Reversal)</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ProvisionForLoanLossesExpensed_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Provision for (recovery of) credit losses on unfunded lending commitments</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="dei_AuditorName_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Auditor Name</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="dei_AuditorName_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Auditor Name</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_StandbyPerformanceLettersOfCreditMember_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Represents information pertaining to standby performance letters of credit.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_StandbyPerformanceLettersOfCreditMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Standby Performance Letters Of Credit [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_StandbyPerformanceLettersOfCreditMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Standby Performance Letters of Credit [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_Deposits_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Deposits</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_Deposits_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Total deposits</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ScheduleOfQuarterlyFinancialInformationTableTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Quarterly Financial Information [Table Text Block]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ScheduleOfQuarterlyFinancialInformationTableTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Quarterly Financial Information</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_PaymentsForProceedsFromLoansReceivable_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Payments for (Proceeds from) Loans Receivable</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_PaymentsForProceedsFromLoansReceivable_lbl" xlink:role="http://www.xbrl.org/2009/role/negatedLabel">Net increase in loans</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_PaymentsForProceedsFromLoansReceivable_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Payments for (Proceeds from) Loans Receivable, Total</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DebtInstrumentFaceAmount_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Debt Instrument, Face Amount</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DebtInstrumentFaceAmount_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Principal amount</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DebtInstrumentFaceAmount_lbl" xlink:role="http://www.xbrl.org/2003/role/verboseLabel">Loans, aggregate balance at origination</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ScheduleOfIntangibleAssetsAndGoodwillTableTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Schedule of Intangible Assets and Goodwill [Table Text Block]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ScheduleOfIntangibleAssetsAndGoodwillTableTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Summary of Goodwill and Other Intangible Assets</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FinancialAssetPastDueMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Financial Asset, Past Due [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FinancialAssetPastDueMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Total Past Due</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FairValueHedgingMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Fair Value Hedging [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FairValueHedgingMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Fair Value Hedging [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_OtherRealEstateAbstract_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Other Real Estate [Abstract]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_AllowanceForLoanAndLeaseLossesWriteOffsCurrentFiscalYear_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Allowance for Loan and Lease Losses Write Offs Current Fiscal Year</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_AllowanceForLoanAndLeaseLossesWriteOffsCurrentFiscalYear_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Allowance for loan and lease losses write offs current fiscal year.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_AllowanceForLoanAndLeaseLossesWriteOffsCurrentFiscalYear_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Current period gross charge-offs, 2025</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FederalHomeLoanBankAdvancesMaturitiesSummaryDueWithinOneYearOfBalanceSheetDate_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Federal Home Loan Bank, Advance, Maturity, Year One</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FederalHomeLoanBankAdvancesMaturitiesSummaryDueWithinOneYearOfBalanceSheetDate_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Federal Home Loan Bank, Advances, Maturities Summary, Due in Next Twelve Months, Total</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FederalHomeLoanBankAdvancesMaturitiesSummaryDueWithinOneYearOfBalanceSheetDate_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Federal Home Loan Bank, Advance, Maturity, Year One, Total</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_InterestAndFeeIncomeLoansAndLeases_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Interest and Fee Income, Loans and Leases</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_InterestAndFeeIncomeLoansAndLeases_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Interest and fees on loans</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_InterestAndFeeIncomeLoansAndLeases_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Interest and Fee Income, Loans and Leases, Total</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AssetPledgedAsCollateralWithRightMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Asset Pledged as Collateral with Right [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AssetPledgedAsCollateralWithRightMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Asset Pledged as Collateral with Right [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_InterestRateFloorMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Interest Rate Floor [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_InterestRateFloorMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Interest Rate Floor [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_BusinessExitCosts1_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Business Exit Costs</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_BusinessExitCosts1_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Lease termination costs</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_OperatingLeaseWeightedAverageRemainingLeaseTerm1_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Operating Lease, Weighted Average Remaining Lease Term</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_OperatingLeaseWeightedAverageRemainingLeaseTerm1_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Weighted-average remaining lease term (in years)</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_TimeDepositMaturitiesYearTwo_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Time Deposit Maturities, Year Two</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_TimeDepositMaturitiesYearTwo_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">2026</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LeaseCost_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Lease, Cost</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LeaseCost_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Operating lease expense</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LeaseCost_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Lease, Cost, Total</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_NumberOfInterestRateFloorContracts_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Number Of Interest Rate Floor Contracts</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_NumberOfInterestRateFloorContracts_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Number of interest rate floor contracts.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_NumberOfInterestRateFloorContracts_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Number of interest rate floor contracts</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_CashAndCashEquivalentsPolicyTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Cash and Cash Equivalents, Policy [Policy Text Block]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_CashAndCashEquivalentsPolicyTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Cash and Cash Equivalents</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_PropertyPlantAndEquipmentNet_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Premises and equipment, net of accumulated depreciation</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_PropertyPlantAndEquipmentNet_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Property, Plant and Equipment, Net</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_PropertyPlantAndEquipmentNet_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Total premises and equipment, net</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LoansAndLeasesReceivableAllowance_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Less allowance for credit losses on loans and leases</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LoansAndLeasesReceivableAllowance_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Loans and leases, allowance for credit losses</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LoansAndLeasesReceivableAllowance_lbl" xlink:role="http://www.xbrl.org/2003/role/periodEndLabel">Ending balance</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LoansAndLeasesReceivableAllowance_lbl" xlink:role="http://www.xbrl.org/2003/role/verboseLabel">Allowance for credit losses on loans and leases</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LoansAndLeasesReceivableAllowance_lbl" xlink:role="http://www.xbrl.org/2009/role/netLabel">Allowance for credit losses</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LoansAndLeasesReceivableAllowance_lbl" xlink:role="http://www.xbrl.org/2003/role/periodStartLabel">Beginning balance</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_SecuredByMultifamilyResidentialPropertiesMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Secured by Multi family Residential Properties [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_SecuredByMultifamilyResidentialPropertiesMember_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Represents information pertaining to loans secured by multi-family residential properties.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_SecuredByMultifamilyResidentialPropertiesMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Secured By Multifamily Residential Properties [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_RetainedEarningsMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Retained Earnings [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_RetainedEarningsMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Retained Earnings [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_OtherLiabilitiesCustomerRelatedInterestRateSwapsThirdPartyCounterparties_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Other liabilities customer related interest rate swaps third party counterparties</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_OtherLiabilitiesCustomerRelatedInterestRateSwapsThirdPartyCounterparties_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Other liabilities customer related interest rate swaps third party counterparties.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ShareBasedCompensation_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Share-Based Payment Arrangement, Noncash Expense</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ShareBasedCompensation_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Stock-based compensation expense</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ShareBasedCompensation_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Share-Based Payment Arrangement, Noncash Expense, Total</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_LoansAndLeasesReceivableAllowanceHeldToMaturity_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Allowance for credit losses, held-to-maturity</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_LoansAndLeasesReceivableAllowanceHeldToMaturity_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Loans and Leases Receivable Allowance, Held-to-Maturity</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_LoansAndLeasesReceivableAllowanceHeldToMaturity_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Loans and leases receivable allowance, held-to-maturity.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LoansInsuredOrGuaranteedByGovernmentAuthoritiesDomain_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Loans Insured or Guaranteed by Government Authorities [Domain]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LoansInsuredOrGuaranteedByGovernmentAuthoritiesDomain_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Loans Insured or Guaranteed by Government Authorities</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="srt_StockRepurchaseProgramNumberOfSharesAuthorizedToBeRepurchased_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Share Repurchase Program, Authorized, Number of Shares</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="srt_StockRepurchaseProgramNumberOfSharesAuthorizedToBeRepurchased_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Authorized purchase of additional shares</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPositionLessThan12Months_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Debt Securities, Available-for-Sale, Continuous Unrealized Loss Position, Less than 12 Months</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPositionLessThan12Months_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Available-for-sale, less than 12 months, fair value</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_OperatingLeaseWeightedAverageDiscountRatePercent_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Operating Lease, Weighted Average Discount Rate, Percent</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_OperatingLeaseWeightedAverageDiscountRatePercent_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Weighted-average discount rate</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FairValueInputsLevel1Member_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Fair Value, Inputs, Level 1 [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FairValueInputsLevel1Member_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Fair Value, Inputs, Level 1 [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_PaymentsForProceedsFromFederalHomeLoanBankStock_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Payments for (Proceeds from) Federal Home Loan Bank Stock</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_PaymentsForProceedsFromFederalHomeLoanBankStock_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Payments for (Proceeds from) Federal Home Loan Bank Stock, Total</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_PaymentsForProceedsFromFederalHomeLoanBankStock_lbl" xlink:role="http://www.xbrl.org/2009/role/negatedLabel">Net decrease (increase) in Federal Home Loan Bank stock</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DisclosureTextBlockAbstract_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Disclosure Text Block [Abstract]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_OtherLiabilitiesCreditRiskParticipationAgreementMember_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Other liabilities - credit risk participation agreement member.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_OtherLiabilitiesCreditRiskParticipationAgreementMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Other Liabilities - Credit Risk Participation Agreements [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_NetCashProvidedByUsedInFinancingActivities_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Cash Provided by (Used in) Financing Activity, Including Discontinued Operation</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_NetCashProvidedByUsedInFinancingActivities_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Net cash provided by financing activities</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_CollateralDomain_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Collateral Held</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_CollateralDomain_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Collateral Held [Domain]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ShortTermDebtLineItems_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Short-Term Debt [Line Items]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ShortTermDebtLineItems_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Short Term Debt [Line Items]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LeaseCostTableTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Lease, Cost [Table Text Block]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LeaseCostTableTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Components of Lease Expense</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FinancingReceivableOriginatedThreeYearsBeforeLatestFiscalYear_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Financing Receivable, Year Four, Originated, Three Years before Current Fiscal Year</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FinancingReceivableOriginatedThreeYearsBeforeLatestFiscalYear_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">2022</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="dei_AuditorLocation_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Auditor Location</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="dei_AuditorLocation_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Auditor Location</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AvailableForSaleSecuritiesDebtMaturitiesAfterFiveThroughTenYearsFairValue_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Debt Securities, Available-for-Sale, Fair Value, Maturity, Allocated and Single Maturity Date, after Year 5 Through 10</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AvailableForSaleSecuritiesDebtMaturitiesAfterFiveThroughTenYearsFairValue_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Available-for-sale, maturing after five to ten years, estimated fair value</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AssetsUnderManagementCarryingAmount_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Assets under Management, Carrying Amount</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AssetsUnderManagementCarryingAmount_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Carrying Amount of the Hedged Assets</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DerivativeContractTypeDomain_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Derivative Contract [Domain]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DerivativeContractTypeDomain_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Derivative Contract</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIForSaleOfSecuritiesNetOfTax_lbl" xlink:role="http://www.xbrl.org/2009/role/negatedLabel">Reclassification adjustment for net losses on securities available-for-sale realized in net income, net of tax expense of $- and $21, respectively</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIForSaleOfSecuritiesNetOfTax_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI for Sale of Securities, Net of Tax</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="srt_ScheduleOfCondensedCashFlowStatementTableTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Condensed Cash Flow Statement [Table Text Block]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="srt_ScheduleOfCondensedCashFlowStatementTableTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Cash Flow Statement</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_IncomeTaxAuthorityDomain_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Income Tax Jurisdiction [Domain]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_IncomeTaxAuthorityDomain_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Income Tax Authority</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="dei_EntityInteractiveDataCurrent_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Entity Interactive Data Current</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="dei_EntityInteractiveDataCurrent_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Entity Interactive Data Current</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_IncomeStatementLocationDomain_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Statement of Income Location, Balance [Domain]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_IncomeStatementLocationDomain_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Income Statement Location</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FairValueDisclosureItemAmountsDomain_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Fair Value Measurement [Domain]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FairValueDisclosureItemAmountsDomain_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Fair Value Measurement</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_NetCashProvidedByUsedInOperatingActivitiesAbstract_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Cash Provided by (Used in) Operating Activity, Including Discontinued Operation [Abstract]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_NetCashProvidedByUsedInOperatingActivitiesAbstract_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Cash flows from operating activities:</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FurnitureAndFixturesMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Furniture and Fixtures [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FurnitureAndFixturesMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Furniture, Fixtures and Equipment [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DebtSecuritiesHeldToMaturityAllowanceForCreditLossTable_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Debt Securities, Held-to-Maturity, Allowance for Credit Loss [Table]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DebtSecuritiesHeldToMaturityAllowanceForCreditLossTable_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Debt Securities Held To Maturity Allowance For Credit Loss [Table]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LoanRestructuringModificationDomain_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Loan Restructuring Modification [Domain]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LoanRestructuringModificationDomain_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Loan Restructuring Modification</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_SegmentReportingRevenueReconcilingItemLineItems_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Segment Reporting, Revenue Reconciling Item [Line Items]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_SegmentReportingRevenueReconcilingItemLineItems_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Segment Reporting Revenue Reconciling Item [Line Items]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_LesseeOperatingLeasePeriodOfOptionToTerminate_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">The period of time in which the lessee holds the option to terminate an operating lease, in 'PnYnMnDTnHnMnS' format. For example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_LesseeOperatingLeasePeriodOfOptionToTerminate_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Lessee Operating Lease Period Of Option To Terminate</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_LesseeOperatingLeasePeriodOfOptionToTerminate_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Lessee, Operating Lease, Period of Option to Terminate</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_FirstUnitedSecurityBankMember_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Represents a business segment of the company.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_FirstUnitedSecurityBankMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">First United Security Bank [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_FirstUnitedSecurityBankMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">FUSB [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_UnrecognizedTaxBenefitsIncomeTaxPenaltiesAccrued_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Unrecognized Tax Benefits, Income Tax Penalties Accrued</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_UnrecognizedTaxBenefitsIncomeTaxPenaltiesAccrued_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Unrecognized Tax Benefits, Income Tax Penalties Accrued</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_Capital_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Banking Regulation, Total Capital, Actual</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_Capital_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Total capital (to risk-weighted assets), Actual Regulatory Capital, Amount</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ComponentsOfDeferredTaxLiabilitiesAbstract_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Components of Deferred Tax Liabilities [Abstract]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ComponentsOfDeferredTaxLiabilitiesAbstract_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Deferred tax liabilities:</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_CommonStockDividendsPerShareDeclared_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Common Stock, Dividends, Per Share, Declared</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_CommonStockDividendsPerShareDeclared_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Dividends per share</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_CommonStockDividendsPerShareDeclared_lbl" xlink:role="http://www.xbrl.org/2003/role/verboseLabel">Common Stock, Dividends, Per Share, Declared</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_CommunicationsAndInformationTechnology_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Communications and Information Technology</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_CommunicationsAndInformationTechnology_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Telephone/data communication</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_CommunicationsAndInformationTechnology_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Communications and Information Technology, Total</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="dei_EntityTaxIdentificationNumber_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Entity Tax Identification Number</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="dei_EntityTaxIdentificationNumber_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Entity Tax Identification Number</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_RevenuesAbstract_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Revenues [Abstract]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_RevenuesAbstract_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Income:</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LandMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Land [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LandMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Land [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LongtermDebtTypeAxis_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Long-Term Debt, Type [Axis]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LongtermDebtTypeAxis_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Long-term Debt, Type</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="srt_CondensedIncomeStatementTable_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Condensed Income Statement [Table]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPositionLessThan12MonthsNumberOfPositions_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Debt Securities, Available-for-Sale, Continuous Unrealized Loss Position, Less than 12 Months, Number of Positions</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPositionLessThan12MonthsNumberOfPositions_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Available-for-sale, Securities in Unrealized Loss Positions, Qualitative Disclosure, Number of Positions, Less than One Year</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ProceedsFromMaturitiesPrepaymentsAndCallsOfAvailableForSaleSecurities_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Proceeds from maturities and prepayments of investment securities, available-for-sale</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ProceedsFromMaturitiesPrepaymentsAndCallsOfAvailableForSaleSecurities_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Proceeds from Maturities, Prepayments and Calls of Debt Securities, Available-for-Sale</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_OccupancyNet_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Occupancy, Net</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_OccupancyNet_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Net occupancy and equipment</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LoansNotesTradeAndOtherReceivablesDisclosureTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Loans and Leases</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LoansNotesTradeAndOtherReceivablesDisclosureTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Loans, Notes, Trade and Other Receivables Disclosure [Text Block]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="dei_LocalPhoneNumber_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Local Phone Number</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="dei_LocalPhoneNumber_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Local Phone Number</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_IncomeTaxReconciliationDeductionsLifeInsuranceAmount_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Income tax reconciliation deductions life insurance amount</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_IncomeTaxReconciliationDeductionsLifeInsuranceAmount_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Income Tax Reconciliation Deductions Life Insurance Amount</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_IncomeTaxReconciliationDeductionsLifeInsuranceAmount_lbl" xlink:role="http://www.xbrl.org/2009/role/negatedLabel">Bank-owned life insurance</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="dei_AuditorOpinionTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Auditor Opinion [Text Block]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ScheduleOfDeferredCompensationArrangementWithIndividualShareBasedPaymentsTable_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Deferred Compensation Arrangement with Individual, Share-Based Payment [Table]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ScheduleOfDeferredCompensationArrangementWithIndividualShareBasedPaymentsTable_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Schedule Of Deferred Compensation Arrangement With Individual Share Based Payments [Table]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_NetDecreaseToIncomeBeforeIncomeTaxesMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Net Decrease to Income Before Income Taxes [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_NetDecreaseToIncomeBeforeIncomeTaxesMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Net Decrease To Income Before Income Taxes [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_NetDecreaseToIncomeBeforeIncomeTaxesMember_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Net decrease to income before income taxes.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_OtherRealEstateOtherAssetsMeasurementInput_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">OREO and other assets held-for-sale</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_OtherRealEstateOtherAssetsMeasurementInput_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Other real estate other assets measurement input.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_OtherRealEstateOtherAssetsMeasurementInput_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Other Real Estate Other Assets Measurement Input</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_OtherRealEstateOtherAssetsMeasurementInput_lbl" xlink:role="http://www.xbrl.org/2003/role/verboseLabel">OREO and other assets held-for-sale</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_NotRatedMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Not Rated [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_NotRatedMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Not Rated [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_NotRatedMember_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Not rated.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ScheduleOfCreditLossesForFinancingReceivablesCurrentTableTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Summary of the Impact on Allowance for Credit Losses on Loans and Leases of the Adoption of ASC 326</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ScheduleOfCreditLossesForFinancingReceivablesCurrentTableTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Financing Receivable, Current, Allowance for Credit Loss [Table Text Block]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_NoninterestExpense_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Noninterest Expense</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_NoninterestExpense_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Total non-interest expense</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_NoninterestExpense_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Total non-interest expense</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_NoninterestExpense_lbl" xlink:role="http://www.xbrl.org/2003/role/verboseLabel">Expense</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ScheduleOfFinancingReceivableRecordedInvestmentCreditQualityIndicatorTable_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Financing Receivable, Credit Quality Indicator [Table]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ScheduleOfFinancingReceivableRecordedInvestmentCreditQualityIndicatorTable_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Schedule Of Financing Receivable Recorded Investment Credit Quality Indicator [Table]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AccountingPoliciesAbstract_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Accounting Policies [Abstract]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DerivativeAverageCapInterestRate_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Derivative, Average Cap Interest Rate</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DerivativeAverageCapInterestRate_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Interest rate cap, strike rate</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_OutsideServicesExpense_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Outside Services Expense</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_OutsideServicesExpense_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Outside services expense.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_OutsideServicesExpense_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Outside services</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_CapitalConservationBufferRate_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Capital conservation buffer rate.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_CapitalConservationBufferRate_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Capital Conservation Buffer Rate</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_CapitalConservationBufferRate_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Capital conservation buffer</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearFour_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">2029</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearFour_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Lessee, Operating Lease, Liability, to be Paid, Year Four</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LaborAndRelatedExpense_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Labor and Related Expense</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LaborAndRelatedExpense_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Salaries and employee benefits</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DefinedContributionPlanMaximumAnnualContributionsPerEmployeePercent_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Defined Contribution Plan, Maximum Annual Contributions Per Employee, Percent</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DefinedContributionPlanMaximumAnnualContributionsPerEmployeePercent_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Defined Contribution Plan, Maximum Annual Contributions Per Employee, Percent</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_SelfInsuranceReserve_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Self Insurance Reserve</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_SelfInsuranceReserve_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Self Insurance Reserve</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="dei_EntityEmergingGrowthCompany_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Entity Emerging Growth Company</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="dei_EntityEmergingGrowthCompany_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Entity Emerging Growth Company</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsVestedAndExpectedToVestOutstandingWeightedAverageRemainingContractualTerm1_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Vested and Expected to Vest, Outstanding, Weighted Average Remaining Contractual Term</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsVestedAndExpectedToVestOutstandingWeightedAverageRemainingContractualTerm1_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Share-based compensation arrangement by share-based payment award, options, vested and expected to vest, outstanding, weighted average remaining contractual term</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FederalHomeLoanBankAdvancesMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Federal Home Loan Bank Advances [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FederalHomeLoanBankAdvancesMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">FHLB Advances [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FederalHomeLoanBankAdvancesMember_lbl" xlink:role="http://www.xbrl.org/2003/role/verboseLabel">FHLB Borrowings [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_ChiefInformationAndConsumerBankingOfficerMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Chief information and consumer banking officer [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_ChiefConsumerLendingOfficerMember_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Chief consumer lending officer.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_ChiefCommercialLendingOfficerMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Chief commercial lending officer [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_ChiefInformationAndConsumerBankingOfficerMember_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Chief information and consumer banking officer.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_ChiefConsumerLendingOfficerMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Chief consumer lending officer [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_ChiefRiskOfficerMember_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Chief risk officer.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_ChiefRiskOfficerMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Chief risk officer [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="fusb_ChiefCommercialLendingOfficerMember_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Chief commercial lending officer.</link:label>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="fusb_OtherAssetsCustomerRelatedInterestRateSwapsBorrowerMember" xlink:to="fusb_OtherAssetsCustomerRelatedInterestRateSwapsBorrowerMember_lbl"/>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ScheduleOfCashFlowSupplementalDisclosuresTableTextBlock" xlink:to="us-gaap_ScheduleOfCashFlowSupplementalDisclosuresTableTextBlock_lbl"/>
          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_IncreaseDecreaseInInterestPayableNet" xlink:to="us-gaap_IncreaseDecreaseInInterestPayableNet_lbl"/>
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          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_SegmentDomain" xlink:to="us-gaap_SegmentDomain_lbl"/>
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          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_OperatingLeaseIncomeComprehensiveIncomeExtensibleList" xlink:to="us-gaap_OperatingLeaseIncomeComprehensiveIncomeExtensibleList_lbl"/>
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          <link:labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="dei_EntityIncorporationStateCountryCode" xlink:to="dei_EntityIncorporationStateCountryCode_lbl"/>
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          <link:loc xlink:type="locator" xlink:href="fusb-20251231.xsd#fusb_ConstructionLandDevelopmentAndOtherLandLoansMember" xlink:label="fusb_ConstructionLandDevelopmentAndOtherLandLoansMember"/>
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          <link:loc xlink:type="locator" xlink:href="fusb-20251231.xsd#fusb_SecuredBy1To4FamilyResidentialPropertiesMember" xlink:label="fusb_SecuredBy1To4FamilyResidentialPropertiesMember"/>
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          <link:loc xlink:type="locator" xlink:href="fusb-20251231.xsd#fusb_BranchRetailMember" xlink:label="fusb_BranchRetailMember"/>
          <link:loc xlink:type="locator" xlink:href="fusb-20251231.xsd#fusb_IndirectMember" xlink:label="fusb_IndirectMember"/>
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        <link:definitionLink xlink:type="extended" xlink:role="http://www.firstusbank.com/20251231/taxonomy/role/DisclosureLoansAndLeasesScheduleOfAmortizedCostBasisOfCollateralDependentLoansDetails">
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          <link:loc xlink:type="locator" xlink:href="fusb-20251231.xsd#fusb_CollateralLoansIndividuallyEvaluatedAmortizedCostBasis" xlink:label="fusb_CollateralLoansIndividuallyEvaluatedAmortizedCostBasis"/>
          <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_CollateralAxis" xlink:label="us-gaap_CollateralAxis"/>
          <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_CollateralDomain" xlink:label="us-gaap_CollateralDomain"/>
          <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_CollateralDomain" xlink:label="us-gaap_CollateralDomain_default"/>
          <link:loc xlink:type="locator" xlink:href="fusb-20251231.xsd#fusb_RealEstate1Member" xlink:label="fusb_RealEstate1Member"/>
          <link:loc xlink:type="locator" xlink:href="fusb-20251231.xsd#fusb_ConstructionLandDevelopmentAndOtherLandLoansMember" xlink:label="fusb_ConstructionLandDevelopmentAndOtherLandLoansMember"/>
          <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RealEstateMember" xlink:label="us-gaap_RealEstateMember"/>
          <link:loc xlink:type="locator" xlink:href="fusb-20251231.xsd#fusb_CommercialAndIndustrialLoansMember" xlink:label="fusb_CommercialAndIndustrialLoansMember"/>
          <link:loc xlink:type="locator" xlink:href="fusb-20251231.xsd#fusb_SecuredByRealEstate1To4FamilyResidentialPropertiesMember" xlink:label="fusb_SecuredByRealEstate1To4FamilyResidentialPropertiesMember"/>
          <link:loc xlink:type="locator" xlink:href="fusb-20251231.xsd#fusb_OtherMember" xlink:label="fusb_OtherMember"/>
          <link:loc xlink:type="locator" xlink:href="fusb-20251231.xsd#fusb_SecuredByMultifamilyResidentialPropertiesMember" xlink:label="fusb_SecuredByMultifamilyResidentialPropertiesMember"/>
          <link:loc xlink:type="locator" xlink:href="fusb-20251231.xsd#fusb_SecuredByNonResidentialCommercialRealEstateMember" xlink:label="fusb_SecuredByNonResidentialCommercialRealEstateMember"/>
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        <link:calculationLink xlink:type="extended" xlink:role="http://www.firstusbank.com/20251231/taxonomy/role/Role_DisclosureFirstUSBancsharesIncParentCompanyOnlyFinancialInformationStatementsOfCashFlowDetail">
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  <xsd:element id="fusb_IncomeTaxDisclosureTable" name="IncomeTaxDisclosureTable" type="xbrli:stringItemType" substitutionGroup="xbrldt:hypercubeItem" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="fusb_ProceedsFromSettlementOfDerivativeContracts" name="ProceedsFromSettlementOfDerivativeContracts" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="debit"/>
  <xsd:element id="fusb_InterestRateFloorsMember" name="InterestRateFloorsMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="fusb_ForwardInterestRateSwapContractsTwoMember" name="ForwardInterestRateSwapContractsTwoMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="fusb_GoodwillAndOtherIntangibleAssetTable" name="GoodwillAndOtherIntangibleAssetTable" type="xbrli:stringItemType" substitutionGroup="xbrldt:hypercubeItem" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="fusb_CreditRiskParticipationAgreementsMember" name="CreditRiskParticipationAgreementsMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="fusb_CommonEquityTierOneRiskBasedCapitalRequiredForCapitalAdequacyToRiskWeightedAssets" name="CommonEquityTierOneRiskBasedCapitalRequiredForCapitalAdequacyToRiskWeightedAssets" type="dtr-types:percentItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false"/>
  <xsd:element id="fusb_PercentageOfLoansAndLeases" name="PercentageOfLoansAndLeases" type="dtr-types:percentItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false"/>
  <xsd:element id="fusb_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsReleasedFromRestrictionInPeriod" name="ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsReleasedFromRestrictionInPeriod" type="xbrli:sharesItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
  <xsd:element id="fusb_LoansNetOfUnamortizedPremiums" name="LoansNetOfUnamortizedPremiums" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false" xbrli:balance="debit"/>
  <xsd:element id="fusb_SecuredBy1To4FamilyResidentialPropertiesMember" name="SecuredBy1To4FamilyResidentialPropertiesMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="fusb_LoansAndLeasesReceivableAllowanceHeldToMaturity" name="LoansAndLeasesReceivableAllowanceHeldToMaturity" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false" xbrli:balance="credit"/>
  <xsd:element id="fusb_OtherComprehensiveIncomeLossReclassificationAdjustmentNetGainsOnCashFlowHedgeDerivativesRealizedInNetIncomeNetOfTax" name="OtherComprehensiveIncomeLossReclassificationAdjustmentNetGainsOnCashFlowHedgeDerivativesRealizedInNetIncomeNetOfTax" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="credit"/>
  <xsd:element id="fusb_OtherLiabilitiesInterestRateSwapsMember" name="OtherLiabilitiesInterestRateSwapsMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="fusb_StatementOfCashFlowsTable" name="StatementOfCashFlowsTable" type="xbrli:stringItemType" substitutionGroup="xbrldt:hypercubeItem" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="fusb_InterestRateSwapOneMember" name="InterestRateSwapOneMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="fusb_SecuredByRealEstate1To4FamilyResidentialPropertiesMember" name="SecuredByRealEstate1To4FamilyResidentialPropertiesMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="fusb_OtherRealEstateGrossGains" name="OtherRealEstateGrossGains" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="credit"/>
  <xsd:element id="fusb_ComputerServicesExpense" name="ComputerServicesExpense" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="debit"/>
  <xsd:element id="fusb_CreditLossesOnUnfundedLendingCommitmentsMember" name="CreditLossesOnUnfundedLendingCommitmentsMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="fusb_CorrespondentBanksMember" name="CorrespondentBanksMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="fusb_InterestRateSwapThreeMember" name="InterestRateSwapThreeMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="fusb_InterestRateSwapsRelatedToFHLBAdvancesMember" name="InterestRateSwapsRelatedToFHLBAdvancesMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="fusb_BalanceSheetRelatedDisclosuresLineItems" name="BalanceSheetRelatedDisclosuresLineItems" type="xbrli:stringItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="fusb_ChiefInformationAndConsumerBankingOfficerMember" name="ChiefInformationAndConsumerBankingOfficerMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="fusb_FederalFundsSoldFairValueDisclosure" name="FederalFundsSoldFairValueDisclosure" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false" xbrli:balance="debit"/>
  <xsd:element id="fusb_ForeclosedRealEstateOwnedFairValueLessDisposalCosts" name="ForeclosedRealEstateOwnedFairValueLessDisposalCosts" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false" xbrli:balance="debit"/>
  <xsd:element id="fusb_GainsLossesOnSalesOfPremisesEquipmentAndOtherRealEstateHeldForSale" name="GainsLossesOnSalesOfPremisesEquipmentAndOtherRealEstateHeldForSale" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="credit"/>
  <xsd:element id="fusb_ImpairedLoansMeasurementInput" name="ImpairedLoansMeasurementInput" type="xbrli:decimalItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false"/>
  <xsd:element id="fusb_OtherIncomeAndExpensesLineItems" name="OtherIncomeAndExpensesLineItems" type="xbrli:stringItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="fusb_IncomeTaxReconciliationDeductionsLifeInsuranceAmount" name="IncomeTaxReconciliationDeductionsLifeInsuranceAmount" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="credit"/>
  <xsd:element id="fusb_FirstUnitedSecurityBankMember" name="FirstUnitedSecurityBankMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="fusb_LongTermDebtAverageRatePaidIncludingAmortizationOfDebtIssuanceCosts" name="LongTermDebtAverageRatePaidIncludingAmortizationOfDebtIssuanceCosts" type="dtr-types:percentItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
  <xsd:element id="fusb_InterestOnDepositsMember" name="InterestOnDepositsMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="fusb_OtherNonInterestIncomeMember" name="OtherNonInterestIncomeMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="fusb_CommercialAndIndustrialLoansMember" name="CommercialAndIndustrialLoansMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="fusb_CumulativeBasisAdjustmentsAssociatedWithHedgingRelationships" name="CumulativeBasisAdjustmentsAssociatedWithHedgingRelationships" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false" xbrli:balance="debit"/>
  <xsd:element id="fusb_RestructuringAndRelatedCostNumberOfOfficeClosed" name="RestructuringAndRelatedCostNumberOfOfficeClosed" type="xbrli:integerItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
  <xsd:element id="fusb_CollectionAndRecoveries" name="CollectionAndRecoveries" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="debit"/>
  <xsd:element id="fusb_AcceptanceLoanCompanyMember" name="AcceptanceLoanCompanyMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="fusb_InterestRateCapOneMember" name="InterestRateCapOneMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="fusb_BalanceSheetRelatedDisclosuresTable" name="BalanceSheetRelatedDisclosuresTable" type="xbrli:stringItemType" substitutionGroup="xbrldt:hypercubeItem" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="fusb_CommercialAndIndustrialLoansAndLeasesMember" name="CommercialAndIndustrialLoansAndLeasesMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="fusb_InterestOnShortTermBorrowingsMember" name="InterestOnShortTermBorrowingsMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="fusb_CollateralDependentLoansFairValueDisclosure" name="CollateralDependentLoansFairValueDisclosure" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false" xbrli:balance="debit"/>
  <xsd:element id="fusb_NetIncreaseDecreaseToIncomeBeforeIncomeTaxesMember" name="NetIncreaseDecreaseToIncomeBeforeIncomeTaxesMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="fusb_ForwardInterestRateSwapContractsOneMember" name="ForwardInterestRateSwapContractsOneMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="fusb_LesseeOperatingLeaseRemainingTermOfContract" name="LesseeOperatingLeaseRemainingTermOfContract" type="xbrli:durationItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
  <xsd:element id="fusb_OutsideServicesExpense" name="OutsideServicesExpense" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="debit"/>
  <xsd:element id="fusb_RestructuredLoanModifiedThroughExtendedMaturityAndPaymentScheduleModificationMember" name="RestructuredLoanModifiedThroughExtendedMaturityAndPaymentScheduleModificationMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="fusb_SecuredByNonResidentialCommercialRealEstateMember" name="SecuredByNonResidentialCommercialRealEstateMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="fusb_LongTermDebtWeightedAverageRemainingMaturityTerm" name="LongTermDebtWeightedAverageRemainingMaturityTerm" type="xbrli:durationItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
  <xsd:element id="fusb_OtherNonInterestExpenseMember" name="OtherNonInterestExpenseMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="fusb_CustomerRelatedInterestRateSwapsThirdPartyCounterpartiesMember" name="CustomerRelatedInterestRateSwapsThirdPartyCounterpartiesMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="fusb_NetDecreaseToIncomeBeforeIncomeTaxesMember" name="NetDecreaseToIncomeBeforeIncomeTaxesMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="fusb_SecuredByNonfarmNonresidentialPropertiesMember" name="SecuredByNonfarmNonresidentialPropertiesMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="fusb_InvestmentIntoCapitalSurplus" name="InvestmentIntoCapitalSurplus" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="debit"/>
  <xsd:element id="fusb_DirectConsumerMember" name="DirectConsumerMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="fusb_ScheduleOfLoanAndLeaseLossesAndRecordedInvestmentInLoansByLoanClassificationAndByImpairmentEvaluationTableTextBlock" name="ScheduleOfLoanAndLeaseLossesAndRecordedInvestmentInLoansByLoanClassificationAndByImpairmentEvaluationTableTextBlock" type="dtr-types:textBlockItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
  <xsd:element id="fusb_IncomeTaxDisclosureLineItems" name="IncomeTaxDisclosureLineItems" type="xbrli:stringItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="fusb_CommonEquityTierOneRiskBasedCapitalRequiredToBeWellCapitalizedToRiskWeightedAsset" name="CommonEquityTierOneRiskBasedCapitalRequiredToBeWellCapitalizedToRiskWeightedAsset" type="dtr-types:percentItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false"/>
  <xsd:element id="fusb_TreasuryStockPolicyTextBlock" name="TreasuryStockPolicyTextBlock" type="dtr-types:textBlockItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
  <xsd:element id="fusb_DefinedContributionPlanDiscretionaryContributionPercent" name="DefinedContributionPlanDiscretionaryContributionPercent" type="dtr-types:percentItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
  <xsd:element id="fusb_NumberOfFullTimeEmploymentPositionsEliminated" name="NumberOfFullTimeEmploymentPositionsEliminated" type="xbrli:integerItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
  <xsd:element id="fusb_ReclassificationOfUnrealizedGainsOnTerminatedDerivativeContracts" name="ReclassificationOfUnrealizedGainsOnTerminatedDerivativeContracts" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="credit"/>
  <xsd:element id="fusb_EmployeeBenefitPlanLineItems" name="EmployeeBenefitPlanLineItems" type="xbrli:stringItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="fusb_OtherRealEstateGrossLosses" name="OtherRealEstateGrossLosses" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="debit"/>
  <xsd:element id="fusb_NumberOfInterestRateFloorContracts" name="NumberOfInterestRateFloorContracts" type="xbrli:integerItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
  <xsd:element id="fusb_OtherIncomeATMFees" name="OtherIncomeATMFees" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="credit"/>
  <xsd:element id="fusb_BankOwnedLifeInsurancePolicyTextBlock" name="BankOwnedLifeInsurancePolicyTextBlock" type="dtr-types:textBlockItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
  <xsd:element id="fusb_PercentageParValueAllowedAsCollateral" name="PercentageParValueAllowedAsCollateral" type="dtr-types:percentItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
  <xsd:element id="fusb_PerformingAndNonPerformingMember" name="PerformingAndNonPerformingMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="fusb_OtherAssetsInterestRateSwapsMember" name="OtherAssetsInterestRateSwapsMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="fusb_NumberOfInterestRateSwapContracts" name="NumberOfInterestRateSwapContracts" type="xbrli:integerItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
  <xsd:element id="fusb_ScheduleOfDerivativeInstrumentsEffectOnStatementOfOperationsTableTextBlock" name="ScheduleOfDerivativeInstrumentsEffectOnStatementOfOperationsTableTextBlock" type="dtr-types:textBlockItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
  <xsd:element id="fusb_ScheduleOfIncomeTaxesPaidNetOfRefundsTableTextBlock" name="ScheduleOfIncomeTaxesPaidNetOfRefundsTableTextBlock" type="dtr-types:textBlockItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
  <xsd:element id="fusb_NumberOfForwardStartingContractsTerminated" name="NumberOfForwardStartingContractsTerminated" type="xbrli:integerItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
  <xsd:element id="fusb_PassAndCriticizedMember" name="PassAndCriticizedMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="fusb_InterestRateSwapsRelatedToFixedRateIndirectConsumerLoansMember" name="InterestRateSwapsRelatedToFixedRateIndirectConsumerLoansMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="fusb_MaximumMaturityPeriodForCashEquivalents" name="MaximumMaturityPeriodForCashEquivalents" type="xbrli:durationItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
  <xsd:element id="fusb_FederalHomeLoanBankAdvancesGeneralDebtObligationsDisclosuresExcessOfCollateralAvailableToUtilizeAdditionalCredit" name="FederalHomeLoanBankAdvancesGeneralDebtObligationsDisclosuresExcessOfCollateralAvailableToUtilizeAdditionalCredit" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false" xbrli:balance="debit"/>
  <xsd:element id="fusb_ChiefConsumerLendingOfficerMember" name="ChiefConsumerLendingOfficerMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="fusb_CreditDerivativesMember" name="CreditDerivativesMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="fusb_ScheduledMaturitiesOfTimeDepositsTableTextBlock" name="ScheduledMaturitiesOfTimeDepositsTableTextBlock" type="dtr-types:textBlockItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
  <xsd:element id="fusb_DeferredTaxLiabilitiesUnrealizedGainsOnCashFlowHedges" name="DeferredTaxLiabilitiesUnrealizedGainsOnCashFlowHedges" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false" xbrli:balance="credit"/>
  <xsd:element id="fusb_PercentageOfLoanPortfolio" name="PercentageOfLoanPortfolio" type="dtr-types:percentItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false"/>
  <xsd:element id="fusb_EmployeesMember" name="EmployeesMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="fusb_MaturityPeriodOfFederalFunds" name="MaturityPeriodOfFederalFunds" type="xbrli:durationItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
  <xsd:element id="fusb_SoftwareMember" name="SoftwareMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="fusb_ScheduleOfAmortizedCostBasisOfCollateralDependentLoansTableTextBlock" name="ScheduleOfAmortizedCostBasisOfCollateralDependentLoansTableTextBlock" type="dtr-types:textBlockItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
  <xsd:element id="fusb_ImpairedLoansFairValue" name="ImpairedLoansFairValue" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false" xbrli:balance="debit"/>
  <xsd:element id="fusb_ForwardInterestRateSwapContractsMember" name="ForwardInterestRateSwapContractsMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="fusb_InterestRateFloorContractsTwoMember" name="InterestRateFloorContractsTwoMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="fusb_PPPLoansMember" name="PPPLoansMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="fusb_EquipmentFinancingLeasesMember" name="EquipmentFinancingLeasesMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="fusb_WeightedAverageNumberOfSharesOutstanding" name="WeightedAverageNumberOfSharesOutstanding" type="xbrli:sharesItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
  <xsd:element id="fusb_InterestRateSwapsRelatedToInterestBearingLiabilitiesMember" name="InterestRateSwapsRelatedToInterestBearingLiabilitiesMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="fusb_NumberOfInterestRateSwapContractsTerminated" name="NumberOfInterestRateSwapContractsTerminated" type="xbrli:integerItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
  <xsd:element id="fusb_AllowanceForLoanAndLeaseLossesWriteOffsTwoYearsBeforeLatestFiscalYear" name="AllowanceForLoanAndLeaseLossesWriteOffsTwoYearsBeforeLatestFiscalYear" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="debit"/>
  <xsd:element id="fusb_ScheduleOfOtherOperatingIncomeByComponentTextBlock" name="ScheduleOfOtherOperatingIncomeByComponentTextBlock" type="dtr-types:textBlockItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
  <xsd:element id="fusb_CollateralLoansIndividuallyEvaluatedAmortizedCostBasis" name="CollateralLoansIndividuallyEvaluatedAmortizedCostBasis" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="debit"/>
  <xsd:element id="fusb_OrganizationConsolidationAndPresentationOfFinancialStatementsTable" name="OrganizationConsolidationAndPresentationOfFinancialStatementsTable" type="xbrli:stringItemType" substitutionGroup="xbrldt:hypercubeItem" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="fusb_EquityInUndistributedEarningsOfSubsidiary" name="EquityInUndistributedEarningsOfSubsidiary" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="credit"/>
  <xsd:element id="fusb_OtherLiabilitiesCustomerRelatedInterestRateSwapsThirdPartyCounterparties" name="OtherLiabilitiesCustomerRelatedInterestRateSwapsThirdPartyCounterparties" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false" xbrli:balance="credit"/>
  <xsd:element id="fusb_ThePeoplesBankMember" name="ThePeoplesBankMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="fusb_OtherIncomeAndExpensesTable" name="OtherIncomeAndExpensesTable" type="xbrli:stringItemType" substitutionGroup="xbrldt:hypercubeItem" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="fusb_NumberOfStates" name="NumberOfStates" type="xbrli:stringItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
  <xsd:element id="fusb_AllowanceForLoanAndLeaseLossesWriteOffsCurrentFiscalYear" name="AllowanceForLoanAndLeaseLossesWriteOffsCurrentFiscalYear" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="debit"/>
  <xsd:element id="fusb_IncreaseDecreaseInFederalFundsSoldAndSecuritiesPurchasedUnderReverseRepurchaseAgreements" name="IncreaseDecreaseInFederalFundsSoldAndSecuritiesPurchasedUnderReverseRepurchaseAgreements" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="debit"/>
  <xsd:element id="fusb_DerivativeInstrumentInterestRateIncreaseDecrease" name="DerivativeInstrumentInterestRateIncreaseDecrease" type="dtr-types:percentItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
  <xsd:element id="fusb_ConstructionLandDevelopmentAndOtherLandLoansMember" name="ConstructionLandDevelopmentAndOtherLandLoansMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="fusb_TerminationOfTechnologyContracts" name="TerminationOfTechnologyContracts" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="debit"/>
  <xsd:element id="fusb_BrokeredCertificatesOfDeposit" name="BrokeredCertificatesOfDeposit" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false" xbrli:balance="credit"/>
  <xsd:element id="fusb_InterestRateSwapsRelatedToFixedRateCommercialRealEstateLoansMember" name="InterestRateSwapsRelatedToFixedRateCommercialRealEstateLoansMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="fusb_LoansAndInterestIncomePolicyTextBlock" name="LoansAndInterestIncomePolicyTextBlock" type="dtr-types:textBlockItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
  <xsd:element id="fusb_InterestIncomeExpenseNetMember" name="InterestIncomeExpenseNetMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="fusb_FederalFundsSoldAndSecuritiesPurchasedUnderReverseRepurchaseAgreementsFairValueDisclosure" name="FederalFundsSoldAndSecuritiesPurchasedUnderReverseRepurchaseAgreementsFairValueDisclosure" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false" xbrli:balance="debit"/>
  <xsd:element id="fusb_AllowanceForLoanAndLeaseLossesWriteOffsFourYearsBeforeLatestFiscalYear" name="AllowanceForLoanAndLeaseLossesWriteOffsFourYearsBeforeLatestFiscalYear" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="debit"/>
  <xsd:element id="fusb_DeferredTaxLiabilitiesPartnerships" name="DeferredTaxLiabilitiesPartnerships" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false" xbrli:balance="credit"/>
  <xsd:element id="fusb_OtherAssetsCustomerRelatedInterestRateSwapsBorrowerMember" name="OtherAssetsCustomerRelatedInterestRateSwapsBorrowerMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="fusb_OtherLiabilitiesCreditRiskParticipationAgreement" name="OtherLiabilitiesCreditRiskParticipationAgreement" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false" xbrli:balance="credit"/>
  <xsd:element id="fusb_ChiefRiskOfficerMember" name="ChiefRiskOfficerMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="fusb_ForwardInterestRateSwapContractsThreeMember" name="ForwardInterestRateSwapContractsThreeMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="fusb_RemainingUnrealizedGainsAssociatedWithTerminatedDerivatives" name="RemainingUnrealizedGainsAssociatedWithTerminatedDerivatives" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="credit"/>
  <xsd:element id="fusb_TransitionAdjustmentIncreaseInLoanLossReserves" name="TransitionAdjustmentIncreaseInLoanLossReserves" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false" xbrli:balance="debit"/>
  <xsd:element id="fusb_InterestAndFeesOnLoansMember" name="InterestAndFeesOnLoansMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="fusb_AllowanceForLoanAndLeaseLossesWriteOffsThreeYearsBeforeLatestFiscalYear" name="AllowanceForLoanAndLeaseLossesWriteOffsThreeYearsBeforeLatestFiscalYear" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="debit"/>
  <xsd:element id="fusb_OtherLiabilitiesCreditRiskParticipationAgreementMember" name="OtherLiabilitiesCreditRiskParticipationAgreementMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="fusb_WeightedAverageDirectorDeferredShares" name="WeightedAverageDirectorDeferredShares" type="xbrli:sharesItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
  <xsd:element id="fusb_ForeclosedRealEstateOtherExpenseNetOfGainOrLossOnSale" name="ForeclosedRealEstateOtherExpenseNetOfGainOrLossOnSale" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="debit"/>
  <xsd:element id="fusb_ProceedsFromSaleOfPremisesAndEquipmentAndOtherRealEstate" name="ProceedsFromSaleOfPremisesAndEquipmentAndOtherRealEstate" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="debit"/>
  <xsd:element id="fusb_IncreaseDecreaseInCashSurrenderValueOfBankOwnedLifeInsurance" name="IncreaseDecreaseInCashSurrenderValueOfBankOwnedLifeInsurance" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="credit"/>
  <xsd:element id="fusb_PercentageOfAssets" name="PercentageOfAssets" type="dtr-types:percentItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false"/>
  <xsd:element id="fusb_LoansHeldForInvestmentMember" name="LoansHeldForInvestmentMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="fusb_IncomeStatementLineItems" name="IncomeStatementLineItems" type="xbrli:stringItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="fusb_OtherRealEstateAssetsAcquiredInForeclosureRollForwardTableTextBlock" name="OtherRealEstateAssetsAcquiredInForeclosureRollForwardTableTextBlock" type="dtr-types:textBlockItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
  <xsd:element id="fusb_OtherAssetsInterestRateCapsMember" name="OtherAssetsInterestRateCapsMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="fusb_DepreciationAndAmortizationOfPropertyPlantAndEquipmentAndComputerPrograms" name="DepreciationAndAmortizationOfPropertyPlantAndEquipmentAndComputerPrograms" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="debit"/>
  <xsd:element id="fusb_RepossessionsPolicyTextBlock" name="RepossessionsPolicyTextBlock" type="dtr-types:textBlockItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
  <xsd:element id="fusb_AmortizedCostBasisOfClosedPortfoliosUsedInHedgingRelationships" name="AmortizedCostBasisOfClosedPortfoliosUsedInHedgingRelationships" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false" xbrli:balance="debit"/>
  <xsd:element id="fusb_DistributionsInExcessOfUndistributedIncomeLossOfSubsidiaries" name="DistributionsInExcessOfUndistributedIncomeLossOfSubsidiaries" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="credit"/>
  <xsd:element id="fusb_PaycheckProtectionProgramMember" name="PaycheckProtectionProgramMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="fusb_CommitmentRequiredForEvaluatingIndividuallyAtManagementDiscretion" name="CommitmentRequiredForEvaluatingIndividuallyAtManagementDiscretion" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false" xbrli:balance="credit"/>
  <xsd:element id="fusb_StandbyPerformanceLettersOfCreditMember" name="StandbyPerformanceLettersOfCreditMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="fusb_CapitalConservationBufferRate" name="CapitalConservationBufferRate" type="dtr-types:percentItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
  <xsd:element id="fusb_InterestRateSwapTwoMember" name="InterestRateSwapTwoMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="fusb_FixedAssetValuationAdjustments" name="FixedAssetValuationAdjustments" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="debit"/>
  <xsd:element id="fusb_PercentageOfLoansAndLeasesCurrent" name="PercentageOfLoansAndLeasesCurrent" type="dtr-types:percentItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false"/>
  <xsd:element id="fusb_OtherAssetsInterestRateCapMember" name="OtherAssetsInterestRateCapMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="fusb_NumberOfSecuritiesHeldAsTradingSecurities" name="NumberOfSecuritiesHeldAsTradingSecurities" type="xbrli:integerItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
  <xsd:element id="fusb_StatementOfCashFlowsLineItems" name="StatementOfCashFlowsLineItems" type="xbrli:stringItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="fusb_OtherRealEstateOtherAssetsMeasurementInput" name="OtherRealEstateOtherAssetsMeasurementInput" type="xbrli:decimalItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false"/>
  <xsd:element id="fusb_CustomerRelatedInterestRateSwapsBorrowerMember" name="CustomerRelatedInterestRateSwapsBorrowerMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="fusb_ChiefCommercialLendingOfficerMember" name="ChiefCommercialLendingOfficerMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="fusb_OtherRealEstateAssetsAcquiredInRepossessionsTableTextBlock" name="OtherRealEstateAssetsAcquiredInRepossessionsTableTextBlock" type="dtr-types:textBlockItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
  <xsd:element id="fusb_LesseeOperatingLeaseLiabilityToBePaidAfterYearFour" name="LesseeOperatingLeaseLiabilityToBePaidAfterYearFour" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false" xbrli:balance="credit"/>
  <xsd:element id="fusb_NumberOfInvestmentPortfolios" name="NumberOfInvestmentPortfolios" type="xbrli:integerItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
  <xsd:element id="fusb_BranchRetailMember" name="BranchRetailMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="fusb_CommitmentsToExtendCredit1Member" name="CommitmentsToExtendCredit1Member" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="fusb_OmnibusIncentivePlanMember" name="OmnibusIncentivePlanMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="fusb_LoansAndLeasesHeldForInvestmentPolicyPolicyTextBlock" name="LoansAndLeasesHeldForInvestmentPolicyPolicyTextBlock" type="dtr-types:textBlockItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
  <xsd:element id="fusb_DescriptionOfMaturityPeriod" name="DescriptionOfMaturityPeriod" type="xbrli:stringItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
  <xsd:element id="fusb_OtherAssetsInterestRateFloorsMember" name="OtherAssetsInterestRateFloorsMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="fusb_NumberOfFullTimeEmployees" name="NumberOfFullTimeEmployees" type="xbrli:integerItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false"/>
  <xsd:element id="fusb_NonEmployeeDirectorsMember" name="NonEmployeeDirectorsMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="fusb_IndirectConsumersMember" name="IndirectConsumersMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="fusb_OtherRealEstateNetIncomeLoss" name="OtherRealEstateNetIncomeLoss" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="credit"/>
  <xsd:element id="fusb_OtherRealEstateOtherAssetsFairValueDisclosure" name="OtherRealEstateOtherAssetsFairValueDisclosure" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false" xbrli:balance="debit"/>
  <xsd:element id="fusb_SecuredByMultifamilyResidentialPropertiesMember" name="SecuredByMultifamilyResidentialPropertiesMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="fusb_FinancingReceivableAllowanceForCreditLossWriteoffAfterRecoveryLineItems" name="FinancingReceivableAllowanceForCreditLossWriteoffAfterRecoveryLineItems" type="xbrli:stringItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="fusb_OrganizationConsolidationAndPresentationOfFinancialStatementsLineItems" name="OrganizationConsolidationAndPresentationOfFinancialStatementsLineItems" type="xbrli:stringItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="fusb_NumberOfCreditRiskParticipationAgreement" name="NumberOfCreditRiskParticipationAgreement" type="xbrli:integerItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
  <xsd:element id="fusb_AllowanceForLoanAndLeaseLossesWriteOffsFiscalYearBeforeLatestFiscalYear" name="AllowanceForLoanAndLeaseLossesWriteOffsFiscalYearBeforeLatestFiscalYear" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="debit"/>
  <xsd:element id="fusb_IncomeLossBeforeEquityInUndistributedIncomeOfSubsidiaries" name="IncomeLossBeforeEquityInUndistributedIncomeOfSubsidiaries" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="credit"/>
  <xsd:element id="fusb_GoodwillAndOtherIntangibleAssetsLineItems" name="GoodwillAndOtherIntangibleAssetsLineItems" type="xbrli:stringItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="fusb_ActiveHedgesMember" name="ActiveHedgesMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="fusb_OtherMember" name="OtherMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="fusb_ScheduleOfInvestmentSecuritiesAvailableForSaleAndHeldToMaturityTableTextBlock" name="ScheduleOfInvestmentSecuritiesAvailableForSaleAndHeldToMaturityTableTextBlock" type="dtr-types:textBlockItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
  <xsd:element id="fusb_ProceedsFromPaymentsRelatedToTaxWithholdingForShareBasedCompensation" name="ProceedsFromPaymentsRelatedToTaxWithholdingForShareBasedCompensation" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="debit"/>
  <xsd:element id="fusb_OtherLiabilitiesCustomerRelatedInterestRateSwapsThirdPartyCounterpartiesMember" name="OtherLiabilitiesCustomerRelatedInterestRateSwapsThirdPartyCounterpartiesMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="fusb_RepossessionsAssetMeasurementInput" name="RepossessionsAssetMeasurementInput" type="xbrli:decimalItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false"/>
  <xsd:element id="fusb_TimeDepositMaturitiesAfterYearFour" name="TimeDepositMaturitiesAfterYearFour" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false" xbrli:balance="credit"/>
  <xsd:element id="fusb_OtherThanTemporaryImpairmentLossDebtSecuritiesAvailableForSaleRecognizedInEarningsInterestRate" name="OtherThanTemporaryImpairmentLossDebtSecuritiesAvailableForSaleRecognizedInEarningsInterestRate" type="dtr-types:percentItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
  <xsd:element id="fusb_RealEstate1Member" name="RealEstate1Member" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="fusb_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsReleasedFromRestrictionInPeriodWeightedAverageGrantDateFairValue" name="ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsReleasedFromRestrictionInPeriodWeightedAverageGrantDateFairValue" type="dtr-types:perShareItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
  <xsd:element id="fusb_NumberOfForwardInterestRateSwapContracts" name="NumberOfForwardInterestRateSwapContracts" type="xbrli:integerItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
  <xsd:element id="fusb_LoansNetOfUnearnedIncomeAndUnamortizedDeferredFeesAndCosts" name="LoansNetOfUnearnedIncomeAndUnamortizedDeferredFeesAndCosts" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false" xbrli:balance="debit"/>
  <xsd:element id="fusb_PercentageOfLoansAndLeasesPastDue" name="PercentageOfLoansAndLeasesPastDue" type="dtr-types:percentItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false"/>
  <xsd:element id="fusb_NotRatedMember" name="NotRatedMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="fusb_CollateralDependentLoansMeasurementInput" name="CollateralDependentLoansMeasurementInput" type="xbrli:decimalItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false"/>
  <xsd:element id="fusb_IndirectMember" name="IndirectMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="fusb_AllowanceForCreditLossesPolicyPolicyTextBlock" name="AllowanceForCreditLossesPolicyPolicyTextBlock" type="dtr-types:textBlockItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
  <xsd:element id="fusb_AllowanceForLoanAndLeaseLossesWriteOffsFiveOrMoreYearsBeforeLatestFiscalYear" name="AllowanceForLoanAndLeaseLossesWriteOffsFiveOrMoreYearsBeforeLatestFiscalYear" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="debit"/>
  <xsd:element id="fusb_DerivativeInstrumentsGainLossReclassifiedFromAccumulatedOCIIntoIncomeEffectivePortionNet1" name="DerivativeInstrumentsGainLossReclassifiedFromAccumulatedOCIIntoIncomeEffectivePortionNet1" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="credit"/>
  <xsd:element id="fusb_FinancingReceivableAllowanceForCreditLossWriteoffAfterRecoveryTable" name="FinancingReceivableAllowanceForCreditLossWriteoffAfterRecoveryTable" type="xbrli:stringItemType" substitutionGroup="xbrldt:hypercubeItem" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="fusb_ScheduleOfDerivativeInstrumentsInStatementOfFinancialPositionNominalAmountAndFairValueTableTextBlock" name="ScheduleOfDerivativeInstrumentsInStatementOfFinancialPositionNominalAmountAndFairValueTableTextBlock" type="dtr-types:textBlockItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
  <xsd:element id="fusb_GainOnSalesOfPremisesAndEquipmentAndOtherAssets" name="GainOnSalesOfPremisesAndEquipmentAndOtherAssets" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="credit"/>
  <xsd:element id="fusb_EmployeeBenefitPlanTable" name="EmployeeBenefitPlanTable" type="xbrli:stringItemType" substitutionGroup="xbrldt:hypercubeItem" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="fusb_MinimumCommitmentRequiredForEvaluatingIdividually" name="MinimumCommitmentRequiredForEvaluatingIdividually" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false" xbrli:balance="credit"/>
  <xsd:element id="fusb_InterestRateCapTwoMember" name="InterestRateCapTwoMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="fusb_InterestRateFloorContractsOneMember" name="InterestRateFloorContractsOneMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="fusb_LesseeOperatingLeasePeriodOfOptionToTerminate" name="LesseeOperatingLeasePeriodOfOptionToTerminate" type="xbrli:durationItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
  <xsd:element id="fusb_HedgeTerminatedInTwoThousandTwentyTwoMember" name="HedgeTerminatedInTwoThousandTwentyTwoMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
</xsd:schema>
