<?xml version="1.0" encoding="US-ASCII" standalone="no"?>
<!--Generated by ThunderDome XBRL - 08:35PM UTC 2026-08-07--><xsd:schema xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:country="http://xbrl.sec.gov/country/2026" xmlns:currency="http://xbrl.sec.gov/currency/2026" xmlns:dei="http://xbrl.sec.gov/dei/2026" xmlns:dtr-types="http://www.xbrl.org/dtr/type/2020-01-21" xmlns:ecd="http://xbrl.sec.gov/ecd/2026" xmlns:enum2="http://xbrl.org/2020/extensible-enumerations-2.0" xmlns:exch="http://xbrl.sec.gov/exch/2026" xmlns:fnrn="http://www.thatsmybank.com/20260630" xmlns:link="http://www.xbrl.org/2003/linkbase" xmlns:naics="http://xbrl.sec.gov/naics/2026" xmlns:sic="http://xbrl.sec.gov/sic/2026" xmlns:srt="http://fasb.org/srt/2026" xmlns:srt-types="http://fasb.org/srt-types/2026" xmlns:stpr="http://xbrl.sec.gov/stpr/2026" xmlns:us-gaap="http://fasb.org/us-gaap/2026" xmlns:us-types="http://fasb.org/us-types/2026" xmlns:xbrldt="http://xbrl.org/2005/xbrldt" xmlns:xbrli="http://www.xbrl.org/2003/instance" xmlns:xlink="http://www.w3.org/1999/xlink" attributeFormDefault="unqualified" elementFormDefault="qualified" targetNamespace="http://www.thatsmybank.com/20260630">
  <xsd:import namespace="http://fasb.org/srt/2026" schemaLocation="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd"/>
  <xsd:import namespace="http://xbrl.sec.gov/ecd/2026" schemaLocation="https://xbrl.sec.gov/ecd/2026/ecd-2026.xsd"/>
  <xsd:import namespace="http://www.xbrl.org/2003/instance" schemaLocation="http://www.xbrl.org/2003/xbrl-instance-2003-12-31.xsd"/>
  <xsd:import namespace="http://xbrl.sec.gov/dei/2026" schemaLocation="https://xbrl.sec.gov/dei/2026/dei-2026.xsd"/>
  <xsd:import namespace="http://xbrl.sec.gov/exch/2026" schemaLocation="https://xbrl.sec.gov/exch/2026/exch-2026.xsd"/>
  <xsd:import namespace="http://xbrl.org/2005/xbrldt" schemaLocation="http://www.xbrl.org/2005/xbrldt-2005.xsd"/>
  <xsd:import namespace="http://xbrl.sec.gov/currency/2026" schemaLocation="https://xbrl.sec.gov/currency/2026/currency-2026.xsd"/>
  <xsd:import namespace="http://xbrl.sec.gov/country/2026" schemaLocation="https://xbrl.sec.gov/country/2026/country-2026.xsd"/>
  <xsd:import namespace="http://xbrl.sec.gov/naics/2026" schemaLocation="https://xbrl.sec.gov/naics/2026/naics-2026.xsd"/>
  <xsd:import namespace="http://www.xbrl.org/dtr/type/2020-01-21" schemaLocation="https://www.xbrl.org/dtr/type/2020-01-21/types.xsd"/>
  <xsd:import namespace="http://xbrl.org/2020/extensible-enumerations-2.0" schemaLocation="https://www.xbrl.org/2020/extensible-enumerations-2.0.xsd"/>
  <xsd:import namespace="http://xbrl.sec.gov/stpr/2026" schemaLocation="https://xbrl.sec.gov/stpr/2026/stpr-2026.xsd"/>
  <xsd:import namespace="http://xbrl.sec.gov/sic/2026" schemaLocation="https://xbrl.sec.gov/sic/2026/sic-2026.xsd"/>
  <xsd:import namespace="http://fasb.org/us-types/2026" schemaLocation="https://xbrl.fasb.org/us-gaap/2026/elts/us-types-2026.xsd"/>
  <xsd:import namespace="http://www.xbrl.org/2009/role/negated" schemaLocation="http://www.xbrl.org/lrr/role/negated-2009-12-16.xsd"/>
  <xsd:import namespace="http://fasb.org/srt-types/2026" schemaLocation="https://xbrl.fasb.org/srt/2026/elts/srt-types-2026.xsd"/>
  <xsd:import namespace="http://fasb.org/us-gaap/2026" schemaLocation="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd"/>
  <xsd:annotation>
    <xsd:appinfo>
      <link:linkbaseRef xlink:arcrole="http://www.w3.org/1999/xlink/properties/linkbase" xlink:href="fnrn-20260630_lab.xml" xlink:role="http://www.xbrl.org/2003/role/labelLinkbaseRef" xlink:type="simple"/>
      <link:linkbaseRef xlink:arcrole="http://www.w3.org/1999/xlink/properties/linkbase" xlink:href="fnrn-20260630_cal.xml" xlink:role="http://www.xbrl.org/2003/role/calculationLinkbaseRef" xlink:type="simple"/>
      <link:linkbaseRef xlink:arcrole="http://www.w3.org/1999/xlink/properties/linkbase" xlink:href="fnrn-20260630_def.xml" xlink:role="http://www.xbrl.org/2003/role/definitionLinkbaseRef" xlink:type="simple"/>
      <link:linkbaseRef xlink:arcrole="http://www.w3.org/1999/xlink/properties/linkbase" xlink:href="fnrn-20260630_pre.xml" xlink:role="http://www.xbrl.org/2003/role/presentationLinkbaseRef" xlink:type="simple"/>
      <link:roleType id="statement-document-and-entity-information" roleURI="http://www.thatsmybank.com/20260630/role/statement-document-and-entity-information">
        <link:definition xmlns="http://www.xbrl.org/2003/linkbase">000 - Document - Document And Entity Information</link:definition>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
        <link:usedOn>link:presentationLink</link:usedOn>
      </link:roleType>
      <link:roleType id="statement-condensed-consolidated-balance-sheets-current-period-unaudited" roleURI="http://www.thatsmybank.com/20260630/role/statement-condensed-consolidated-balance-sheets-current-period-unaudited">
        <link:definition xmlns="http://www.xbrl.org/2003/linkbase">001 - Statement - Condensed Consolidated Balance Sheets (Current Period Unaudited)</link:definition>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
        <link:usedOn>link:presentationLink</link:usedOn>
      </link:roleType>
      <link:roleType id="statement-condensed-consolidated-balance-sheets-current-period-unaudited-parentheticals" roleURI="http://www.thatsmybank.com/20260630/role/statement-condensed-consolidated-balance-sheets-current-period-unaudited-parentheticals">
        <link:definition xmlns="http://www.xbrl.org/2003/linkbase">002 - Statement - Condensed Consolidated Balance Sheets (Current Period Unaudited) (Parentheticals)</link:definition>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
        <link:usedOn>link:presentationLink</link:usedOn>
      </link:roleType>
      <link:roleType id="statement-condensed-consolidated-statements-of-income-unaudited" roleURI="http://www.thatsmybank.com/20260630/role/statement-condensed-consolidated-statements-of-income-unaudited">
        <link:definition xmlns="http://www.xbrl.org/2003/linkbase">003 - Statement - Condensed Consolidated Statements of Income (Unaudited)</link:definition>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
        <link:usedOn>link:presentationLink</link:usedOn>
      </link:roleType>
      <link:roleType id="statement-condensed-consolidated-statements-of-comprehensive-income-unaudited" roleURI="http://www.thatsmybank.com/20260630/role/statement-condensed-consolidated-statements-of-comprehensive-income-unaudited">
        <link:definition xmlns="http://www.xbrl.org/2003/linkbase">004 - Statement - Condensed Consolidated Statements of Comprehensive Income (Unaudited)</link:definition>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
        <link:usedOn>link:presentationLink</link:usedOn>
      </link:roleType>
      <link:roleType id="statement-condensed-consolidated-statements-of-comprehensive-income-unaudited-parentheticals" roleURI="http://www.thatsmybank.com/20260630/role/statement-condensed-consolidated-statements-of-comprehensive-income-unaudited-parentheticals">
        <link:definition xmlns="http://www.xbrl.org/2003/linkbase">005 - Statement - Condensed Consolidated Statements of Comprehensive Income (Unaudited) (Parentheticals)</link:definition>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
        <link:usedOn>link:presentationLink</link:usedOn>
      </link:roleType>
      <link:roleType id="statement-condensed-consolidated-statements-of-stockholders-equity-unaudited" roleURI="http://www.thatsmybank.com/20260630/role/statement-condensed-consolidated-statements-of-stockholders-equity-unaudited">
        <link:definition xmlns="http://www.xbrl.org/2003/linkbase">006 - Statement - Condensed Consolidated Statements of Stockholders' Equity (Unaudited)</link:definition>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
        <link:usedOn>link:presentationLink</link:usedOn>
      </link:roleType>
      <link:roleType id="statement-condensed-consolidated-statements-of-cash-flows-unaudited" roleURI="http://www.thatsmybank.com/20260630/role/statement-condensed-consolidated-statements-of-cash-flows-unaudited">
        <link:definition xmlns="http://www.xbrl.org/2003/linkbase">007 - Statement - Condensed Consolidated Statements of Cash Flows (Unaudited)</link:definition>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
        <link:usedOn>link:presentationLink</link:usedOn>
      </link:roleType>
      <link:roleType id="statement-note-1-basis-of-presentation" roleURI="http://www.thatsmybank.com/20260630/role/statement-note-1-basis-of-presentation">
        <link:definition xmlns="http://www.xbrl.org/2003/linkbase">008 - Disclosure - Note 1 - Basis of Presentation</link:definition>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
        <link:usedOn>link:presentationLink</link:usedOn>
      </link:roleType>
      <link:roleType id="statement-note-2-accounting-policies" roleURI="http://www.thatsmybank.com/20260630/role/statement-note-2-accounting-policies">
        <link:definition xmlns="http://www.xbrl.org/2003/linkbase">009 - Disclosure - Note 2 - Accounting Policies</link:definition>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
        <link:usedOn>link:presentationLink</link:usedOn>
      </link:roleType>
      <link:roleType id="statement-note-3-investment-securities" roleURI="http://www.thatsmybank.com/20260630/role/statement-note-3-investment-securities">
        <link:definition xmlns="http://www.xbrl.org/2003/linkbase">010 - Disclosure - Note 3 - Investment Securities</link:definition>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
        <link:usedOn>link:presentationLink</link:usedOn>
      </link:roleType>
      <link:roleType id="statement-note-4-loans-and-allowance-for-credit-losses" roleURI="http://www.thatsmybank.com/20260630/role/statement-note-4-loans-and-allowance-for-credit-losses">
        <link:definition xmlns="http://www.xbrl.org/2003/linkbase">011 - Disclosure - Note 4 - Loans and Allowance for Credit Losses</link:definition>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
        <link:usedOn>link:presentationLink</link:usedOn>
      </link:roleType>
      <link:roleType id="statement-note-5-mortgage-operations-" roleURI="http://www.thatsmybank.com/20260630/role/statement-note-5-mortgage-operations-">
        <link:definition xmlns="http://www.xbrl.org/2003/linkbase">012 - Disclosure - Note 5 - Mortgage Operations</link:definition>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
        <link:usedOn>link:presentationLink</link:usedOn>
      </link:roleType>
      <link:roleType id="statement-note-6-fair-value-measurements" roleURI="http://www.thatsmybank.com/20260630/role/statement-note-6-fair-value-measurements">
        <link:definition xmlns="http://www.xbrl.org/2003/linkbase">013 - Disclosure - Note 6 - Fair Value Measurements</link:definition>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
        <link:usedOn>link:presentationLink</link:usedOn>
      </link:roleType>
      <link:roleType id="statement-note-7-commitments-and-contingencies" roleURI="http://www.thatsmybank.com/20260630/role/statement-note-7-commitments-and-contingencies">
        <link:definition xmlns="http://www.xbrl.org/2003/linkbase">014 - Disclosure - Note 7 - Commitments and Contingencies</link:definition>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
        <link:usedOn>link:presentationLink</link:usedOn>
      </link:roleType>
      <link:roleType id="statement-note-8-stock-plans" roleURI="http://www.thatsmybank.com/20260630/role/statement-note-8-stock-plans">
        <link:definition xmlns="http://www.xbrl.org/2003/linkbase">015 - Disclosure - Note 8 - Stock Plans</link:definition>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
        <link:usedOn>link:presentationLink</link:usedOn>
      </link:roleType>
      <link:roleType id="statement-note-9-accumulated-other-comprehensive-loss" roleURI="http://www.thatsmybank.com/20260630/role/statement-note-9-accumulated-other-comprehensive-loss">
        <link:definition xmlns="http://www.xbrl.org/2003/linkbase">016 - Disclosure - Note 9 - Accumulated Other Comprehensive Loss</link:definition>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
        <link:usedOn>link:presentationLink</link:usedOn>
      </link:roleType>
      <link:roleType id="statement-note-10-outstanding-shares-and-earnings-per-share" roleURI="http://www.thatsmybank.com/20260630/role/statement-note-10-outstanding-shares-and-earnings-per-share">
        <link:definition xmlns="http://www.xbrl.org/2003/linkbase">017 - Disclosure - Note 10 - Outstanding Shares and Earnings Per Share</link:definition>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
        <link:usedOn>link:presentationLink</link:usedOn>
      </link:roleType>
      <link:roleType id="statement-note-11-leases" roleURI="http://www.thatsmybank.com/20260630/role/statement-note-11-leases">
        <link:definition xmlns="http://www.xbrl.org/2003/linkbase">018 - Disclosure - Note 11 - Leases</link:definition>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
        <link:usedOn>link:presentationLink</link:usedOn>
      </link:roleType>
      <link:roleType id="statement-note-12-segment-disclosures" roleURI="http://www.thatsmybank.com/20260630/role/statement-note-12-segment-disclosures">
        <link:definition xmlns="http://www.xbrl.org/2003/linkbase">019 - Disclosure - Note 12 - Segment Disclosures</link:definition>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
        <link:usedOn>link:presentationLink</link:usedOn>
      </link:roleType>
      <link:roleType id="statement-significant-accounting-policies-policies" roleURI="http://www.thatsmybank.com/20260630/role/statement-significant-accounting-policies-policies">
        <link:definition xmlns="http://www.xbrl.org/2003/linkbase">995466 - Disclosure - Significant Accounting Policies (Policies)</link:definition>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
        <link:usedOn>link:presentationLink</link:usedOn>
      </link:roleType>
      <link:roleType id="statement-note-3-investment-securities-tables" roleURI="http://www.thatsmybank.com/20260630/role/statement-note-3-investment-securities-tables">
        <link:definition xmlns="http://www.xbrl.org/2003/linkbase">995467 - Disclosure - Note 3 - Investment Securities (Tables)</link:definition>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
        <link:usedOn>link:presentationLink</link:usedOn>
      </link:roleType>
      <link:roleType id="statement-note-4-loans-and-allowance-for-credit-losses-tables" roleURI="http://www.thatsmybank.com/20260630/role/statement-note-4-loans-and-allowance-for-credit-losses-tables">
        <link:definition xmlns="http://www.xbrl.org/2003/linkbase">995468 - Disclosure - Note 4 - Loans and Allowance for Credit Losses (Tables)</link:definition>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
        <link:usedOn>link:presentationLink</link:usedOn>
      </link:roleType>
      <link:roleType id="statement-note-5-mortgage-operations-tables" roleURI="http://www.thatsmybank.com/20260630/role/statement-note-5-mortgage-operations-tables">
        <link:definition xmlns="http://www.xbrl.org/2003/linkbase">995469 - Disclosure - Note 5 - Mortgage Operations (Tables)</link:definition>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
        <link:usedOn>link:presentationLink</link:usedOn>
      </link:roleType>
      <link:roleType id="statement-note-6-fair-value-measurements-tables" roleURI="http://www.thatsmybank.com/20260630/role/statement-note-6-fair-value-measurements-tables">
        <link:definition xmlns="http://www.xbrl.org/2003/linkbase">995470 - Disclosure - Note 6 - Fair Value Measurements (Tables)</link:definition>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
        <link:usedOn>link:presentationLink</link:usedOn>
      </link:roleType>
      <link:roleType id="statement-note-7-commitments-and-contingencies-tables" roleURI="http://www.thatsmybank.com/20260630/role/statement-note-7-commitments-and-contingencies-tables">
        <link:definition xmlns="http://www.xbrl.org/2003/linkbase">995471 - Disclosure - Note 7 - Commitments and Contingencies (Tables)</link:definition>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
        <link:usedOn>link:presentationLink</link:usedOn>
      </link:roleType>
      <link:roleType id="statement-note-8-stock-plans-tables" roleURI="http://www.thatsmybank.com/20260630/role/statement-note-8-stock-plans-tables">
        <link:definition xmlns="http://www.xbrl.org/2003/linkbase">995472 - Disclosure - Note 8 - Stock Plans (Tables)</link:definition>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
        <link:usedOn>link:presentationLink</link:usedOn>
      </link:roleType>
      <link:roleType id="statement-note-9-accumulated-other-comprehensive-loss-tables" roleURI="http://www.thatsmybank.com/20260630/role/statement-note-9-accumulated-other-comprehensive-loss-tables">
        <link:definition xmlns="http://www.xbrl.org/2003/linkbase">995473 - Disclosure - Note 9 - Accumulated Other Comprehensive Loss (Tables)</link:definition>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
        <link:usedOn>link:presentationLink</link:usedOn>
      </link:roleType>
      <link:roleType id="statement-note-10-outstanding-shares-and-earnings-per-share-tables" roleURI="http://www.thatsmybank.com/20260630/role/statement-note-10-outstanding-shares-and-earnings-per-share-tables">
        <link:definition xmlns="http://www.xbrl.org/2003/linkbase">995474 - Disclosure - Note 10 - Outstanding Shares and Earnings Per Share (Tables)</link:definition>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
        <link:usedOn>link:presentationLink</link:usedOn>
      </link:roleType>
      <link:roleType id="statement-note-11-leases-tables" roleURI="http://www.thatsmybank.com/20260630/role/statement-note-11-leases-tables">
        <link:definition xmlns="http://www.xbrl.org/2003/linkbase">995475 - Disclosure - Note 11 - Leases (Tables)</link:definition>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
        <link:usedOn>link:presentationLink</link:usedOn>
      </link:roleType>
      <link:roleType id="statement-note-3-investment-securities-details-textual" roleURI="http://www.thatsmybank.com/20260630/role/statement-note-3-investment-securities-details-textual">
        <link:definition xmlns="http://www.xbrl.org/2003/linkbase">995476 - Disclosure - Note 3 - Investment Securities (Details Textual)</link:definition>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
        <link:usedOn>link:presentationLink</link:usedOn>
      </link:roleType>
      <link:roleType id="statement-note-3-investment-securities-schedule-of-marketable-securities-details" roleURI="http://www.thatsmybank.com/20260630/role/statement-note-3-investment-securities-schedule-of-marketable-securities-details">
        <link:definition xmlns="http://www.xbrl.org/2003/linkbase">995477 - Disclosure - Note 3 - Investment Securities - Schedule of Marketable Securities (Details)</link:definition>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
        <link:usedOn>link:presentationLink</link:usedOn>
      </link:roleType>
      <link:roleType id="statement-note-3-investments-schedule-of-contractual-maturities-details" roleURI="http://www.thatsmybank.com/20260630/role/statement-note-3-investments-schedule-of-contractual-maturities-details">
        <link:definition xmlns="http://www.xbrl.org/2003/linkbase">995478 - Disclosure - Note 3 - Investments - Schedule of Contractual Maturities (Details)</link:definition>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
        <link:usedOn>link:presentationLink</link:usedOn>
      </link:roleType>
      <link:roleType id="statement-note-3-investment-securities-schedule-of-debt-securities-availableforsale-unrealized-loss-position-fair-value-details" roleURI="http://www.thatsmybank.com/20260630/role/statement-note-3-investment-securities-schedule-of-debt-securities-availableforsale-unrealized-loss-position-fair-value-details">
        <link:definition xmlns="http://www.xbrl.org/2003/linkbase">995479 - Disclosure - Note 3 - Investment Securities - Schedule of Debt Securities, Available-for-Sale, Unrealized Loss Position, Fair Value (Details)</link:definition>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
        <link:usedOn>link:presentationLink</link:usedOn>
      </link:roleType>
      <link:roleType id="statement-note-4-loans-and-allowance-for-credit-losses-details-textual" roleURI="http://www.thatsmybank.com/20260630/role/statement-note-4-loans-and-allowance-for-credit-losses-details-textual">
        <link:definition xmlns="http://www.xbrl.org/2003/linkbase">995480 - Disclosure - Note 4 - Loans and Allowance for Credit Losses (Details Textual)</link:definition>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
        <link:usedOn>link:presentationLink</link:usedOn>
      </link:roleType>
      <link:roleType id="statement-note-4-loans-and-allowance-for-credit-losses-schedule-of-total-loans-outstanding-by-portfolio-segment-details" roleURI="http://www.thatsmybank.com/20260630/role/statement-note-4-loans-and-allowance-for-credit-losses-schedule-of-total-loans-outstanding-by-portfolio-segment-details">
        <link:definition xmlns="http://www.xbrl.org/2003/linkbase">995481 - Disclosure - Note 4 - Loans and Allowance for Credit Losses - Schedule of Total Loans Outstanding by Portfolio Segment (Details)</link:definition>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
        <link:usedOn>link:presentationLink</link:usedOn>
      </link:roleType>
      <link:roleType id="statement-note-4-loans-and-allowance-for-credit-losses-allowance-for-loan-losses-by-portfolio-segment-details" roleURI="http://www.thatsmybank.com/20260630/role/statement-note-4-loans-and-allowance-for-credit-losses-allowance-for-loan-losses-by-portfolio-segment-details">
        <link:definition xmlns="http://www.xbrl.org/2003/linkbase">995482 - Disclosure - Note 4 - Loans and Allowance for Credit Losses - Allowance for Loan Losses by Portfolio Segment (Details)</link:definition>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
        <link:usedOn>link:presentationLink</link:usedOn>
      </link:roleType>
      <link:roleType id="statement-note-4-loans-and-allowance-for-credit-losses-schedule-of-collateral-dependent-loans-details" roleURI="http://www.thatsmybank.com/20260630/role/statement-note-4-loans-and-allowance-for-credit-losses-schedule-of-collateral-dependent-loans-details">
        <link:definition xmlns="http://www.xbrl.org/2003/linkbase">995483 - Disclosure - Note 4 - Loans and Allowance for Credit Losses - Schedule of Collateral Dependent Loans (Details)</link:definition>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
        <link:usedOn>link:presentationLink</link:usedOn>
      </link:roleType>
      <link:roleType id="statement-note-4-loans-and-allowance-for-credit-losses-schedule-of-loans-past-due-details" roleURI="http://www.thatsmybank.com/20260630/role/statement-note-4-loans-and-allowance-for-credit-losses-schedule-of-loans-past-due-details">
        <link:definition xmlns="http://www.xbrl.org/2003/linkbase">995484 - Disclosure - Note 4 - Loans and Allowance for Credit Losses - Schedule of Loans Past Due (Details)</link:definition>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
        <link:usedOn>link:presentationLink</link:usedOn>
      </link:roleType>
      <link:roleType id="statement-note-4-loans-and-allowance-for-credit-losses-schedule-of-modified-financing-receivables-details" roleURI="http://www.thatsmybank.com/20260630/role/statement-note-4-loans-and-allowance-for-credit-losses-schedule-of-modified-financing-receivables-details">
        <link:definition xmlns="http://www.xbrl.org/2003/linkbase">995485 - Disclosure - Note 4 - Loans and Allowance for Credit Losses - Schedule of Modified Financing Receivables (Details)</link:definition>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
        <link:usedOn>link:presentationLink</link:usedOn>
      </link:roleType>
      <link:roleType id="statement-note-4-loans-and-allowance-for-credit-losses-schedule-of-financing-receivable-credit-quality-indicators-details" roleURI="http://www.thatsmybank.com/20260630/role/statement-note-4-loans-and-allowance-for-credit-losses-schedule-of-financing-receivable-credit-quality-indicators-details">
        <link:definition xmlns="http://www.xbrl.org/2003/linkbase">995486 - Disclosure - Note 4 - Loans and Allowance for Credit Losses - Schedule of Financing Receivable Credit Quality Indicators (Details)</link:definition>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
        <link:usedOn>link:presentationLink</link:usedOn>
      </link:roleType>
      <link:roleType id="statement-note-5-mortgage-operations-details-textual" roleURI="http://www.thatsmybank.com/20260630/role/statement-note-5-mortgage-operations-details-textual">
        <link:definition xmlns="http://www.xbrl.org/2003/linkbase">995487 - Disclosure - Note 5 - Mortgage Operations (Details Textual)</link:definition>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
        <link:usedOn>link:presentationLink</link:usedOn>
      </link:roleType>
      <link:roleType id="statement-note-5-mortgage-operations-schedule-of-assumptions-for-fair-value-as-of-balance-sheet-date-of-assets-or-liabilities-that-relate-to-transferors-continuing-involvement-details" roleURI="http://www.thatsmybank.com/20260630/role/statement-note-5-mortgage-operations-schedule-of-assumptions-for-fair-value-as-of-balance-sheet-date-of-assets-or-liabilities-that-relate-to-transferors-continuing-involvement-details">
        <link:definition xmlns="http://www.xbrl.org/2003/linkbase">995488 - Disclosure - Note 5 - Mortgage Operations - Schedule of Assumptions for Fair Value as of Balance Sheet Date of Assets or Liabilities that relate to Transferor's Continuing Involvement (Details)</link:definition>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
        <link:usedOn>link:presentationLink</link:usedOn>
      </link:roleType>
      <link:roleType id="statement-note-5-mortgage-operations-schedule-of-servicing-assets-at-amortized-value-details" roleURI="http://www.thatsmybank.com/20260630/role/statement-note-5-mortgage-operations-schedule-of-servicing-assets-at-amortized-value-details">
        <link:definition xmlns="http://www.xbrl.org/2003/linkbase">995489 - Disclosure - Note 5 - Mortgage Operations - Schedule of Servicing Assets, At Amortized Value (Details)</link:definition>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
        <link:usedOn>link:presentationLink</link:usedOn>
      </link:roleType>
      <link:roleType id="statement-note-6-fair-value-measurements-details-textual" roleURI="http://www.thatsmybank.com/20260630/role/statement-note-6-fair-value-measurements-details-textual">
        <link:definition xmlns="http://www.xbrl.org/2003/linkbase">995490 - Disclosure - Note 6 - Fair Value Measurements (Details Textual)</link:definition>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
        <link:usedOn>link:presentationLink</link:usedOn>
      </link:roleType>
      <link:roleType id="statement-note-6-fair-value-measurements-schedule-of-fair-value-assets-and-liabilities-measured-on-recurring-basis-details" roleURI="http://www.thatsmybank.com/20260630/role/statement-note-6-fair-value-measurements-schedule-of-fair-value-assets-and-liabilities-measured-on-recurring-basis-details">
        <link:definition xmlns="http://www.xbrl.org/2003/linkbase">995491 - Disclosure - Note 6 - Fair Value Measurements - Schedule of Fair Value, Assets and Liabilities Measured on Recurring Basis (Details)</link:definition>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
        <link:usedOn>link:presentationLink</link:usedOn>
      </link:roleType>
      <link:roleType id="statement-note-6-fair-value-measurements-schedule-of-fair-value-assets-measured-on-nonrecurring-basis-details" roleURI="http://www.thatsmybank.com/20260630/role/statement-note-6-fair-value-measurements-schedule-of-fair-value-assets-measured-on-nonrecurring-basis-details">
        <link:definition xmlns="http://www.xbrl.org/2003/linkbase">995492 - Disclosure - Note 6 - Fair Value Measurements - Schedule of Fair Value Assets Measured on Nonrecurring Basis (Details)</link:definition>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
        <link:usedOn>link:presentationLink</link:usedOn>
      </link:roleType>
      <link:roleType id="statement-note-6-fair-value-measurements-schedule-of-fair-value-by-balance-sheet-grouping-details" roleURI="http://www.thatsmybank.com/20260630/role/statement-note-6-fair-value-measurements-schedule-of-fair-value-by-balance-sheet-grouping-details">
        <link:definition xmlns="http://www.xbrl.org/2003/linkbase">995493 - Disclosure - Note 6 - Fair Value Measurements - Schedule of Fair Value by Balance Sheet Grouping (Details)</link:definition>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
        <link:usedOn>link:presentationLink</link:usedOn>
      </link:roleType>
      <link:roleType id="statement-note-7-commitments-and-contingencies-details-textual" roleURI="http://www.thatsmybank.com/20260630/role/statement-note-7-commitments-and-contingencies-details-textual">
        <link:definition xmlns="http://www.xbrl.org/2003/linkbase">995494 - Disclosure - Note 7 - Commitments and Contingencies (Details Textual)</link:definition>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
        <link:usedOn>link:presentationLink</link:usedOn>
      </link:roleType>
      <link:roleType id="statement-note-7-commitments-and-contingencies-schedule-of-fair-value-offbalancesheet-risks-details" roleURI="http://www.thatsmybank.com/20260630/role/statement-note-7-commitments-and-contingencies-schedule-of-fair-value-offbalancesheet-risks-details">
        <link:definition xmlns="http://www.xbrl.org/2003/linkbase">995495 - Disclosure - Note 7 - Commitments and Contingencies - Schedule of Fair Value, off-Balance-Sheet Risks (Details)</link:definition>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
        <link:usedOn>link:presentationLink</link:usedOn>
      </link:roleType>
      <link:roleType id="statement-note-8-stock-plans-details-textual" roleURI="http://www.thatsmybank.com/20260630/role/statement-note-8-stock-plans-details-textual">
        <link:definition xmlns="http://www.xbrl.org/2003/linkbase">995496 - Disclosure - Note 8 - Stock Plans (Details Textual)</link:definition>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
        <link:usedOn>link:presentationLink</link:usedOn>
      </link:roleType>
      <link:roleType id="statement-note-8-stock-plans-schedule-of-stock-option-activity-details" roleURI="http://www.thatsmybank.com/20260630/role/statement-note-8-stock-plans-schedule-of-stock-option-activity-details">
        <link:definition xmlns="http://www.xbrl.org/2003/linkbase">995497 - Disclosure - Note 8 - Stock Plans - Schedule of Stock Option Activity (Details)</link:definition>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
        <link:usedOn>link:presentationLink</link:usedOn>
      </link:roleType>
      <link:roleType id="statement-note-8-stock-plans-schedule-of-restricted-stock-activity-details" roleURI="http://www.thatsmybank.com/20260630/role/statement-note-8-stock-plans-schedule-of-restricted-stock-activity-details">
        <link:definition xmlns="http://www.xbrl.org/2003/linkbase">995498 - Disclosure - Note 8 - Stock Plans - Schedule of Restricted Stock Activity (Details)</link:definition>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
        <link:usedOn>link:presentationLink</link:usedOn>
      </link:roleType>
      <link:roleType id="statement-note-8-stock-plans-schedule-of-sharebased-payment-award-employee-stock-purchase-plan-valuation-assumptions-details" roleURI="http://www.thatsmybank.com/20260630/role/statement-note-8-stock-plans-schedule-of-sharebased-payment-award-employee-stock-purchase-plan-valuation-assumptions-details">
        <link:definition xmlns="http://www.xbrl.org/2003/linkbase">995499 - Disclosure - Note 8 - Stock Plans - Schedule of Share-Based Payment Award, Employee Stock Purchase Plan, Valuation Assumptions (Details)</link:definition>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
        <link:usedOn>link:presentationLink</link:usedOn>
      </link:roleType>
      <link:roleType id="statement-note-9-accumulated-other-comprehensive-loss-schedule-of-accumulated-other-comprehensive-income-loss-details" roleURI="http://www.thatsmybank.com/20260630/role/statement-note-9-accumulated-other-comprehensive-loss-schedule-of-accumulated-other-comprehensive-income-loss-details">
        <link:definition xmlns="http://www.xbrl.org/2003/linkbase">995500 - Disclosure - Note 9 - Accumulated Other Comprehensive Loss - Schedule of Accumulated Other Comprehensive Income (Loss) (Details)</link:definition>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
        <link:usedOn>link:presentationLink</link:usedOn>
      </link:roleType>
      <link:roleType id="statement-note-10-outstanding-shares-and-earnings-per-share-details-textual" roleURI="http://www.thatsmybank.com/20260630/role/statement-note-10-outstanding-shares-and-earnings-per-share-details-textual">
        <link:definition xmlns="http://www.xbrl.org/2003/linkbase">995501 - Disclosure - Note 10 - Outstanding Shares and Earnings Per Share (Details Textual)</link:definition>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
        <link:usedOn>link:presentationLink</link:usedOn>
      </link:roleType>
      <link:roleType id="statement-note-10-outstanding-shares-and-earnings-per-share-schedule-of-earnings-per-share-basic-and-diluted-details" roleURI="http://www.thatsmybank.com/20260630/role/statement-note-10-outstanding-shares-and-earnings-per-share-schedule-of-earnings-per-share-basic-and-diluted-details">
        <link:definition xmlns="http://www.xbrl.org/2003/linkbase">995502 - Disclosure - Note 10 - Outstanding Shares and Earnings Per Share - Schedule of Earnings Per Share, Basic and Diluted (Details)</link:definition>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
        <link:usedOn>link:presentationLink</link:usedOn>
      </link:roleType>
      <link:roleType id="statement-note-11-leases-details-textual" roleURI="http://www.thatsmybank.com/20260630/role/statement-note-11-leases-details-textual">
        <link:definition xmlns="http://www.xbrl.org/2003/linkbase">995503 - Disclosure - Note 11 - Leases (Details Textual)</link:definition>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
        <link:usedOn>link:presentationLink</link:usedOn>
      </link:roleType>
      <link:roleType id="statement-note-11-leases-schedule-of-operating-lease-liability-maturities-details" roleURI="http://www.thatsmybank.com/20260630/role/statement-note-11-leases-schedule-of-operating-lease-liability-maturities-details">
        <link:definition xmlns="http://www.xbrl.org/2003/linkbase">995504 - Disclosure - Note 11 - Leases - Schedule of Operating Lease Liability Maturities (Details)</link:definition>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
        <link:usedOn>link:presentationLink</link:usedOn>
      </link:roleType>
      <link:roleType id="statement-note-11-leases-schedule-of-supplemental-information-details" roleURI="http://www.thatsmybank.com/20260630/role/statement-note-11-leases-schedule-of-supplemental-information-details">
        <link:definition xmlns="http://www.xbrl.org/2003/linkbase">995505 - Disclosure - Note 11 - Leases - Schedule of Supplemental Information (Details)</link:definition>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
        <link:usedOn>link:presentationLink</link:usedOn>
      </link:roleType>
      <link:roleType id="statement-note-12-segment-disclosures-details-textual" roleURI="http://www.thatsmybank.com/20260630/role/statement-note-12-segment-disclosures-details-textual">
        <link:definition xmlns="http://www.xbrl.org/2003/linkbase">995506 - Disclosure - Note 12 - Segment Disclosures (Details Textual)</link:definition>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
        <link:usedOn>link:presentationLink</link:usedOn>
      </link:roleType>
    </xsd:appinfo>
  </xsd:annotation>
  <xsd:element abstract="true" id="fnrn_AgriculturalPortfolioSegmentMember" name="AgriculturalPortfolioSegmentMember" nillable="true" substitutionGroup="xbrli:item" type="dtr-types:domainItemType" xbrli:periodType="duration"/>
  <xsd:element abstract="true" id="fnrn_AgricultureProductionLoansMember" name="AgricultureProductionLoansMember" nillable="true" substitutionGroup="xbrli:item" type="dtr-types:domainItemType" xbrli:periodType="duration"/>
  <xsd:element id="fnrn_CashDividendsPaidInLieuOfFractionalShares" name="CashDividendsPaidInLieuOfFractionalShares" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="duration"/>
  <xsd:element id="fnrn_CashPaidInLieuOfFractionalSharesStockIssued" name="CashPaidInLieuOfFractionalSharesStockIssued" nillable="true" substitutionGroup="xbrli:item" type="xbrli:sharesItemType" xbrli:periodType="duration"/>
  <xsd:element id="fnrn_CashPaidInLieuOfFractionalSharesValue" name="CashPaidInLieuOfFractionalSharesValue" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="duration"/>
  <xsd:element id="fnrn_CertificateOfDepositsFairValueDisclosure" name="CertificateOfDepositsFairValueDisclosure" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="instant"/>
  <xsd:element abstract="true" id="fnrn_CollateralDependentLoansMember" name="CollateralDependentLoansMember" nillable="true" substitutionGroup="xbrli:item" type="dtr-types:domainItemType" xbrli:periodType="duration"/>
  <xsd:element abstract="true" id="fnrn_CollateralMarketIncomeEnterpriseLiquidationMethodsMember" name="CollateralMarketIncomeEnterpriseLiquidationMethodsMember" nillable="true" substitutionGroup="xbrli:item" type="dtr-types:domainItemType" xbrli:periodType="duration"/>
  <xsd:element id="fnrn_DepositsSavingsDepositsAndMoneyMarketDeposits" name="DepositsSavingsDepositsAndMoneyMarketDeposits" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="instant"/>
  <xsd:element abstract="true" id="fnrn_DocumentAndEntityInformation" name="DocumentAndEntityInformation" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration"/>
  <xsd:element abstract="true" id="fnrn_EmployeeStockPurchasePlanMember" name="EmployeeStockPurchasePlanMember" nillable="true" substitutionGroup="xbrli:item" type="dtr-types:domainItemType" xbrli:periodType="duration"/>
  <xsd:element abstract="true" id="fnrn_ExtendedMaturityAndPaymentDeferralMember" name="ExtendedMaturityAndPaymentDeferralMember" nillable="true" substitutionGroup="xbrli:item" type="dtr-types:domainItemType" xbrli:periodType="duration"/>
  <xsd:element abstract="true" id="fnrn_FarmlandMember" name="FarmlandMember" nillable="true" substitutionGroup="xbrli:item" type="dtr-types:domainItemType" xbrli:periodType="duration"/>
  <xsd:element id="fnrn_FederalHomeLoanBankStockAndEquitySecurities" name="FederalHomeLoanBankStockAndEquitySecurities" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="instant"/>
  <xsd:element abstract="true" id="fnrn_FinancialAssetPastDueAndNonaccrualMember" name="FinancialAssetPastDueAndNonaccrualMember" nillable="true" substitutionGroup="xbrli:item" type="dtr-types:domainItemType" xbrli:periodType="duration"/>
  <xsd:element id="fnrn_FinancingReceivableCollateralDependentLoansTableTextBlock" name="FinancingReceivableCollateralDependentLoansTableTextBlock" nillable="true" substitutionGroup="xbrli:item" type="dtr-types:textBlockItemType" xbrli:periodType="duration"/>
  <xsd:element id="fnrn_FinancingReceivableExcludingAccruedInterestAllowanceForCreditLossAndReserveForUnfundedCommitments" name="FinancingReceivableExcludingAccruedInterestAllowanceForCreditLossAndReserveForUnfundedCommitments" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="instant"/>
  <xsd:element id="fnrn_FinancingReceivableExcludingAccruedInterestAllowanceForCreditLossAndReserveForUnfundedCommitmentsChargeoffs" name="FinancingReceivableExcludingAccruedInterestAllowanceForCreditLossAndReserveForUnfundedCommitmentsChargeoffs" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="duration"/>
  <xsd:element id="fnrn_FinancingReceivableExcludingAccruedInterestAllowanceForCreditLossAndReserveForUnfundedCommitmentsRecovery" name="FinancingReceivableExcludingAccruedInterestAllowanceForCreditLossAndReserveForUnfundedCommitmentsRecovery" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="duration"/>
  <xsd:element id="fnrn_FinancingReceivableExcludingAccruedInterestNetChargeoffs" name="FinancingReceivableExcludingAccruedInterestNetChargeoffs" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="instant"/>
  <xsd:element id="fnrn_FinancingReceivableExcludingAccruedInterestOriginatedMoreThanFiveYearsBeforeCurrentFiscalYearNetChargeoffs" name="FinancingReceivableExcludingAccruedInterestOriginatedMoreThanFiveYearsBeforeCurrentFiscalYearNetChargeoffs" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="duration"/>
  <xsd:element id="fnrn_FinancingReceivableExcludingAccruedInterestOriginatedMoreThanFiveYearsBeforeCurrentFiscalYearRecoveries" name="FinancingReceivableExcludingAccruedInterestOriginatedMoreThanFiveYearsBeforeCurrentFiscalYearRecoveries" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="duration"/>
  <xsd:element id="fnrn_FinancingReceivableExcludingAccruedInterestRecoveries" name="FinancingReceivableExcludingAccruedInterestRecoveries" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="duration"/>
  <xsd:element id="fnrn_FinancingReceivableExcludingAccruedInterestRevolvingNetChargeoffs" name="FinancingReceivableExcludingAccruedInterestRevolvingNetChargeoffs" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="duration"/>
  <xsd:element id="fnrn_FinancingReceivableExcludingAccruedInterestRevolvingRecoveries" name="FinancingReceivableExcludingAccruedInterestRevolvingRecoveries" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="duration"/>
  <xsd:element id="fnrn_FinancingReceivableExcludingAccruedInterestYearFiveOriginatedFourYearsBeforeCurrentFiscalYearNetChargeoffs" name="FinancingReceivableExcludingAccruedInterestYearFiveOriginatedFourYearsBeforeCurrentFiscalYearNetChargeoffs" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="duration"/>
  <xsd:element id="fnrn_FinancingReceivableExcludingAccruedInterestYearFiveOriginatedFourYearsBeforeCurrentFiscalYearRecoveries" name="FinancingReceivableExcludingAccruedInterestYearFiveOriginatedFourYearsBeforeCurrentFiscalYearRecoveries" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="duration"/>
  <xsd:element id="fnrn_FinancingReceivableExcludingAccruedInterestYearFourOriginatedThreeYearsBeforeCurrentFiscalYearNetChargeoffs" name="FinancingReceivableExcludingAccruedInterestYearFourOriginatedThreeYearsBeforeCurrentFiscalYearNetChargeoffs" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="duration"/>
  <xsd:element id="fnrn_FinancingReceivableExcludingAccruedInterestYearFourOriginatedThreeYearsBeforeCurrentFiscalYearRecoveries" name="FinancingReceivableExcludingAccruedInterestYearFourOriginatedThreeYearsBeforeCurrentFiscalYearRecoveries" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="duration"/>
  <xsd:element id="fnrn_FinancingReceivableExcludingAccruedInterestYearOneOriginatedCurrentFiscalYearNetChargeoffs" name="FinancingReceivableExcludingAccruedInterestYearOneOriginatedCurrentFiscalYearNetChargeoffs" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="duration"/>
  <xsd:element id="fnrn_FinancingReceivableExcludingAccruedInterestYearOneOriginatedCurrentFiscalYearRecoveries" name="FinancingReceivableExcludingAccruedInterestYearOneOriginatedCurrentFiscalYearRecoveries" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="duration"/>
  <xsd:element id="fnrn_FinancingReceivableExcludingAccruedInterestYearThreeOriginatedTwoYearsBeforeCurrentFiscalYearNetChargeoffs" name="FinancingReceivableExcludingAccruedInterestYearThreeOriginatedTwoYearsBeforeCurrentFiscalYearNetChargeoffs" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="duration"/>
  <xsd:element id="fnrn_FinancingReceivableExcludingAccruedInterestYearThreeOriginatedTwoYearsBeforeCurrentFiscalYearRecoveries" name="FinancingReceivableExcludingAccruedInterestYearThreeOriginatedTwoYearsBeforeCurrentFiscalYearRecoveries" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="duration"/>
  <xsd:element id="fnrn_FinancingReceivableExcludingAccruedInterestYearTwoOriginatedFiscalYearBeforeCurrentFiscalYearNetChargeoffs" name="FinancingReceivableExcludingAccruedInterestYearTwoOriginatedFiscalYearBeforeCurrentFiscalYearNetChargeoffs" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="duration"/>
  <xsd:element id="fnrn_FinancingReceivableExcludingAccruedInterestYearTwoOriginatedFiscalYearBeforeCurrentFiscalYearRecoveries" name="FinancingReceivableExcludingAccruedInterestYearTwoOriginatedFiscalYearBeforeCurrentFiscalYearRecoveries" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="duration"/>
  <xsd:element id="fnrn_ImpairedLoansMeasurementInput" name="ImpairedLoansMeasurementInput" nillable="true" substitutionGroup="xbrli:item" type="xbrli:pureItemType" xbrli:periodType="instant"/>
  <xsd:element id="fnrn_InterestPayableFairValueDisclosure" name="InterestPayableFairValueDisclosure" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="instant"/>
  <xsd:element id="fnrn_InterestReceivableFairValueDisclosure" name="InterestReceivableFairValueDisclosure" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="instant"/>
  <xsd:element id="fnrn_InvestmentInFederalHomeLoanBankStockAndOtherEquitySecuritiesFairValueDisclosure" name="InvestmentInFederalHomeLoanBankStockAndOtherEquitySecuritiesFairValueDisclosure" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="instant"/>
  <xsd:element id="fnrn_LesseeOperatingLeaseLiabilityPaymentsDueAfterYearFour" name="LesseeOperatingLeaseLiabilityPaymentsDueAfterYearFour" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="instant"/>
  <xsd:element id="fnrn_LesseeOperatingLeaseNumberOfBranchAndAdministrativeLocations" name="LesseeOperatingLeaseNumberOfBranchAndAdministrativeLocations" nillable="true" substitutionGroup="xbrli:item" type="xbrli:integerItemType" xbrli:periodType="duration"/>
  <xsd:element id="fnrn_LesseeOperatingLeaseSupplementalCashFlowInformationTableTextBlock" name="LesseeOperatingLeaseSupplementalCashFlowInformationTableTextBlock" nillable="true" substitutionGroup="xbrli:item" type="dtr-types:textBlockItemType" xbrli:periodType="duration"/>
  <xsd:element abstract="true" id="fnrn_LoanServicingMember" name="LoanServicingMember" nillable="true" substitutionGroup="xbrli:item" type="dtr-types:domainItemType" xbrli:periodType="duration"/>
  <xsd:element id="fnrn_MarketValueOfSharesTenderedInlieuOfCashToPayForExerciseOfOptions" name="MarketValueOfSharesTenderedInlieuOfCashToPayForExerciseOfOptions" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="duration"/>
  <xsd:element id="fnrn_MortgageLoansOnRealEstateServicedForOhers" name="MortgageLoansOnRealEstateServicedForOhers" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="instant"/>
  <xsd:element abstract="true" id="fnrn_NoteToFinancialStatementDetailsTextual" name="NoteToFinancialStatementDetailsTextual" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration"/>
  <xsd:element abstract="true" id="fnrn_NotesToFinancialStatements" name="NotesToFinancialStatements" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration"/>
  <xsd:element abstract="true" id="fnrn_NotesToFinancialStatementsAbstract" name="NotesToFinancialStatementsAbstract" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration"/>
  <xsd:element abstract="true" id="fnrn_O2026Q1DividendsMember" name="O2026Q1DividendsMember" nillable="true" substitutionGroup="xbrli:item" type="dtr-types:domainItemType" xbrli:periodType="duration"/>
  <xsd:element id="fnrn_OffBalanceSheetCreditLossLiabilityChargeoffs" name="OffBalanceSheetCreditLossLiabilityChargeoffs" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="duration"/>
  <xsd:element id="fnrn_OffBalanceSheetCreditLossLiabilityRecoveries" name="OffBalanceSheetCreditLossLiabilityRecoveries" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="duration"/>
  <xsd:element abstract="true" id="fnrn_OtherNonfarmNonresidentialPropertiesMember" name="OtherNonfarmNonresidentialPropertiesMember" nillable="true" substitutionGroup="xbrli:item" type="dtr-types:domainItemType" xbrli:periodType="duration"/>
  <xsd:element abstract="true" id="fnrn_OwneroccupiedNonfarmNonresidentialPropertiesMember" name="OwneroccupiedNonfarmNonresidentialPropertiesMember" nillable="true" substitutionGroup="xbrli:item" type="dtr-types:domainItemType" xbrli:periodType="duration"/>
  <xsd:element id="fnrn_PercentageOfEmployeeCompensationThatCanBeWithheldToPurchaseCommonStock" name="PercentageOfEmployeeCompensationThatCanBeWithheldToPurchaseCommonStock" nillable="true" substitutionGroup="xbrli:item" type="dtr-types:percentItemType" xbrli:periodType="duration"/>
  <xsd:element abstract="true" id="fnrn_PolicyTable" name="PolicyTable" nillable="true" substitutionGroup="xbrldt:hypercubeItem" type="xbrli:stringItemType" xbrli:periodType="duration"/>
  <xsd:element id="fnrn_ProceedsFromMaturitiesOfCertificatesOfDeposit" name="ProceedsFromMaturitiesOfCertificatesOfDeposit" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="duration"/>
  <xsd:element id="fnrn_ProceedsFromPrincipalRepaymentsOfAvailableforsaleSecurities" name="ProceedsFromPrincipalRepaymentsOfAvailableforsaleSecurities" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="duration"/>
  <xsd:element abstract="true" id="fnrn_PublicDepositsOrOtherPurposesMember" name="PublicDepositsOrOtherPurposesMember" nillable="true" substitutionGroup="xbrli:item" type="dtr-types:domainItemType" xbrli:periodType="duration"/>
  <xsd:element abstract="true" id="fnrn_RealEstateFirstLienMember" name="RealEstateFirstLienMember" nillable="true" substitutionGroup="xbrli:item" type="dtr-types:domainItemType" xbrli:periodType="duration"/>
  <xsd:element abstract="true" id="fnrn_RealEstateJuniorLienMember" name="RealEstateJuniorLienMember" nillable="true" substitutionGroup="xbrli:item" type="dtr-types:domainItemType" xbrli:periodType="duration"/>
  <xsd:element abstract="true" id="fnrn_RealEstateRevolvingLiensMember" name="RealEstateRevolvingLiensMember" nillable="true" substitutionGroup="xbrli:item" type="dtr-types:domainItemType" xbrli:periodType="duration"/>
  <xsd:element id="fnrn_ServicingAssetAtAmortizedCostNetOfValuationAllowance" name="ServicingAssetAtAmortizedCostNetOfValuationAllowance" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="instant"/>
  <xsd:element id="fnrn_ServicingAssetAtAmortizedCostNetOfValuationAllowanceAdditions" name="ServicingAssetAtAmortizedCostNetOfValuationAllowanceAdditions" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="duration"/>
  <xsd:element id="fnrn_ServicingAssetAtAmortizedCostNetOfValuationAllowanceReductions" name="ServicingAssetAtAmortizedCostNetOfValuationAllowanceReductions" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="duration"/>
  <xsd:element id="fnrn_StockDividendDeclaredPercentage" name="StockDividendDeclaredPercentage" nillable="true" substitutionGroup="xbrli:item" type="dtr-types:percentItemType" xbrli:periodType="duration"/>
  <xsd:element id="fnrn_StockPlanParticipationPeriod" name="StockPlanParticipationPeriod" nillable="true" substitutionGroup="xbrli:item" type="xbrli:durationItemType" xbrli:periodType="duration"/>
  <xsd:element id="fnrn_StockPurchasePricePercentageOfPrice" name="StockPurchasePricePercentageOfPrice" nillable="true" substitutionGroup="xbrli:item" type="dtr-types:percentItemType" xbrli:periodType="duration"/>
  <xsd:element id="fnrn_TimeDeposits250000OrLess" name="TimeDeposits250000OrLess" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="instant"/>
  <xsd:element id="fnrn_TimeDepositsOver250000" name="TimeDepositsOver250000" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="instant"/>
  <xsd:element id="fnrn_TransferOfPremisesAndEquipmentToOtherRealEstateOwned" name="TransferOfPremisesAndEquipmentToOtherRealEstateOwned" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="duration"/>
  <xsd:element abstract="true" id="fnrn_statement-statement-note-10-outstanding-shares-and-earnings-per-share-schedule-of-earnings-per-share-basic-and-diluted-details" name="statement-statement-note-10-outstanding-shares-and-earnings-per-share-schedule-of-earnings-per-share-basic-and-diluted-details" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration"/>
  <xsd:element abstract="true" id="fnrn_statement-statement-note-10-outstanding-shares-and-earnings-per-share-tables" name="statement-statement-note-10-outstanding-shares-and-earnings-per-share-tables" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration"/>
  <xsd:element abstract="true" id="fnrn_statement-statement-note-11-leases-schedule-of-operating-lease-liability-maturities-details" name="statement-statement-note-11-leases-schedule-of-operating-lease-liability-maturities-details" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration"/>
  <xsd:element abstract="true" id="fnrn_statement-statement-note-11-leases-schedule-of-supplemental-information-details" name="statement-statement-note-11-leases-schedule-of-supplemental-information-details" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration"/>
  <xsd:element abstract="true" id="fnrn_statement-statement-note-11-leases-tables" name="statement-statement-note-11-leases-tables" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration"/>
  <xsd:element abstract="true" id="fnrn_statement-statement-note-3-investment-securities-schedule-of-debt-securities-availableforsale-unrealized-loss-position-fair-value-details" name="statement-statement-note-3-investment-securities-schedule-of-debt-securities-availableforsale-unrealized-loss-position-fair-value-details" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration"/>
  <xsd:element abstract="true" id="fnrn_statement-statement-note-3-investment-securities-schedule-of-marketable-securities-details" name="statement-statement-note-3-investment-securities-schedule-of-marketable-securities-details" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration"/>
  <xsd:element abstract="true" id="fnrn_statement-statement-note-3-investment-securities-tables" name="statement-statement-note-3-investment-securities-tables" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration"/>
  <xsd:element abstract="true" id="fnrn_statement-statement-note-3-investments-schedule-of-contractual-maturities-details" name="statement-statement-note-3-investments-schedule-of-contractual-maturities-details" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration"/>
  <xsd:element abstract="true" id="fnrn_statement-statement-note-4-loans-and-allowance-for-credit-losses-allowance-for-loan-losses-by-portfolio-segment-details" name="statement-statement-note-4-loans-and-allowance-for-credit-losses-allowance-for-loan-losses-by-portfolio-segment-details" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration"/>
  <xsd:element abstract="true" id="fnrn_statement-statement-note-4-loans-and-allowance-for-credit-losses-schedule-of-collateral-dependent-loans-details" name="statement-statement-note-4-loans-and-allowance-for-credit-losses-schedule-of-collateral-dependent-loans-details" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration"/>
  <xsd:element abstract="true" id="fnrn_statement-statement-note-4-loans-and-allowance-for-credit-losses-schedule-of-financing-receivable-credit-quality-indicators-details" name="statement-statement-note-4-loans-and-allowance-for-credit-losses-schedule-of-financing-receivable-credit-quality-indicators-details" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration"/>
  <xsd:element abstract="true" id="fnrn_statement-statement-note-4-loans-and-allowance-for-credit-losses-schedule-of-loans-past-due-details" name="statement-statement-note-4-loans-and-allowance-for-credit-losses-schedule-of-loans-past-due-details" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration"/>
  <xsd:element abstract="true" id="fnrn_statement-statement-note-4-loans-and-allowance-for-credit-losses-schedule-of-modified-financing-receivables-details" name="statement-statement-note-4-loans-and-allowance-for-credit-losses-schedule-of-modified-financing-receivables-details" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration"/>
  <xsd:element abstract="true" id="fnrn_statement-statement-note-4-loans-and-allowance-for-credit-losses-schedule-of-total-loans-outstanding-by-portfolio-segment-details" name="statement-statement-note-4-loans-and-allowance-for-credit-losses-schedule-of-total-loans-outstanding-by-portfolio-segment-details" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration"/>
  <xsd:element abstract="true" id="fnrn_statement-statement-note-4-loans-and-allowance-for-credit-losses-tables" name="statement-statement-note-4-loans-and-allowance-for-credit-losses-tables" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration"/>
  <xsd:element abstract="true" id="fnrn_statement-statement-note-5-mortgage-operations-schedule-of-assumptions-for-fair-value-as-of-balance-sheet-date-of-assets-or-liabilities-that-relate-to-transferors-continuing-involvement-details" name="statement-statement-note-5-mortgage-operations-schedule-of-assumptions-for-fair-value-as-of-balance-sheet-date-of-assets-or-liabilities-that-relate-to-transferors-continuing-involvement-details" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration"/>
  <xsd:element abstract="true" id="fnrn_statement-statement-note-5-mortgage-operations-schedule-of-servicing-assets-at-amortized-value-details" name="statement-statement-note-5-mortgage-operations-schedule-of-servicing-assets-at-amortized-value-details" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration"/>
  <xsd:element abstract="true" id="fnrn_statement-statement-note-5-mortgage-operations-tables" name="statement-statement-note-5-mortgage-operations-tables" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration"/>
  <xsd:element abstract="true" id="fnrn_statement-statement-note-6-fair-value-measurements-schedule-of-fair-value-assets-and-liabilities-measured-on-recurring-basis-details" name="statement-statement-note-6-fair-value-measurements-schedule-of-fair-value-assets-and-liabilities-measured-on-recurring-basis-details" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration"/>
  <xsd:element abstract="true" id="fnrn_statement-statement-note-6-fair-value-measurements-schedule-of-fair-value-assets-measured-on-nonrecurring-basis-details" name="statement-statement-note-6-fair-value-measurements-schedule-of-fair-value-assets-measured-on-nonrecurring-basis-details" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration"/>
  <xsd:element abstract="true" id="fnrn_statement-statement-note-6-fair-value-measurements-schedule-of-fair-value-by-balance-sheet-grouping-details" name="statement-statement-note-6-fair-value-measurements-schedule-of-fair-value-by-balance-sheet-grouping-details" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration"/>
  <xsd:element abstract="true" id="fnrn_statement-statement-note-6-fair-value-measurements-tables" name="statement-statement-note-6-fair-value-measurements-tables" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration"/>
  <xsd:element abstract="true" id="fnrn_statement-statement-note-7-commitments-and-contingencies-schedule-of-fair-value-offbalancesheet-risks-details" name="statement-statement-note-7-commitments-and-contingencies-schedule-of-fair-value-offbalancesheet-risks-details" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration"/>
  <xsd:element abstract="true" id="fnrn_statement-statement-note-7-commitments-and-contingencies-tables" name="statement-statement-note-7-commitments-and-contingencies-tables" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration"/>
  <xsd:element abstract="true" id="fnrn_statement-statement-note-8-stock-plans-schedule-of-restricted-stock-activity-details" name="statement-statement-note-8-stock-plans-schedule-of-restricted-stock-activity-details" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration"/>
  <xsd:element abstract="true" id="fnrn_statement-statement-note-8-stock-plans-schedule-of-sharebased-payment-award-employee-stock-purchase-plan-valuation-assumptions-details" name="statement-statement-note-8-stock-plans-schedule-of-sharebased-payment-award-employee-stock-purchase-plan-valuation-assumptions-details" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration"/>
  <xsd:element abstract="true" id="fnrn_statement-statement-note-8-stock-plans-schedule-of-stock-option-activity-details" name="statement-statement-note-8-stock-plans-schedule-of-stock-option-activity-details" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration"/>
  <xsd:element abstract="true" id="fnrn_statement-statement-note-8-stock-plans-tables" name="statement-statement-note-8-stock-plans-tables" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration"/>
  <xsd:element abstract="true" id="fnrn_statement-statement-note-9-accumulated-other-comprehensive-loss-schedule-of-accumulated-other-comprehensive-income-loss-details" name="statement-statement-note-9-accumulated-other-comprehensive-loss-schedule-of-accumulated-other-comprehensive-income-loss-details" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration"/>
  <xsd:element abstract="true" id="fnrn_statement-statement-note-9-accumulated-other-comprehensive-loss-tables" name="statement-statement-note-9-accumulated-other-comprehensive-loss-tables" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration"/>
  <xsd:element abstract="true" id="fnrn_statement-statement-significant-accounting-policies-policies" name="statement-statement-significant-accounting-policies-policies" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration"/>
</xsd:schema>
