v3.26.1
Shareholder Report
 6 Months Ended
Apr. 30, 2026
USD ($)
Holding
Shareholder Report [Line Items]  
Document Type N-CSRS
Amendment Flag false
Registrant Name T. ROWE PRICE SUMMIT MUNICIPAL FUNDS, INC.
Entity Central Index Key 0000912029
Entity Investment Company Type N-1A
Document Period End Date Apr. 30, 2026
C000005553  
Shareholder Report [Line Items]  
Fund Name Summit Municipal Income Fund
Class Name Investor Class
Trading Symbol PRINX
Annual or Semi-Annual Statement [Text Block] This semi-annual shareholder report contains important information about Summit Municipal Income Fund (the "fund") for the period of November 1, 2025 to April 30, 2026.
Shareholder Report Annual or Semi-Annual Semi-Annual Shareholder Report
Additional Information [Text Block] You can find the fund’s prospectus, financial information on Form N‑CSR (which includes required tax information for dividends), holdings, proxy voting information, and other information atwww.troweprice.com/prospectus. You can also request this information without charge by contacting T. Rowe Price at 1‑800‑638‑5660 or info@troweprice.com or contacting your intermediary.
Material Fund Change Notice [Text Block]  
Additional Information Phone Number 1‑800‑638‑5660
Additional Information Email <span style="box-sizing: border-box; color: rgb(0, 0, 0); display: inline; flex-wrap: nowrap; font-size: 13.3333px; font-weight: 400; grid-area: auto; line-height: 17.3333px; margin: 0px; overflow: visible; text-align: justify; text-align-last: left; white-space-collapse: preserve-breaks;">info@troweprice.com</span>
Additional Information Website www.troweprice.com/prospectus
Expenses [Text Block]

What were the fund costs for the last six months? (based on a hypothetical $10,000 investment)

Table Summary
 
Costs of a $10,000 investment
Costs paid as a percentage of a $10,000 investment
Summit Municipal Income Fund - Investor Class
$23
0.45%
Expenses Paid, Amount $ 23
Expense Ratio, Percent 0.45%
AssetsNet $ 2,585,498,000
Holdings Count | Holding 818
InvestmentCompanyPortfolioTurnover 8.50%
Additional Fund Statistics [Text Block]

What are some fund statistics?

Fund Statistics

Table Summary
Total Net Assets (000s)
$2,585,498
Number of Portfolio Holdings
818
Holdings [Text Block]

State Allocation (as a % of Net Assets)

Table Summary
Texas
11.6%
New York
8.6
California
8.3
Georgia
5.1
Maryland
4.8
Puerto Rico
4.7
Florida
4.1
District of Columbia
3.6
Virginia
3.3
Other
45.9
Largest Holdings [Text Block]

Industry Allocation (as a % of Net Assets)

Table Summary
Transportation
23.0%
Health Care
14.2
Special Tax
12.3
Housing
9.4
Education
7.9
General Obligations - State
6.0
General Obligations - Local
5.2
Water & Sewer
2.6
Leasing
2.2
Other
17.2
Material Fund Change [Text Block]
Updated Prospectus Web Address www.troweprice.com/paperless
C000117204  
Shareholder Report [Line Items]  
Fund Name Summit Municipal Income Fund
Class Name Advisor Class
Trading Symbol PAIMX
Annual or Semi-Annual Statement [Text Block] This semi-annual shareholder report contains important information about Summit Municipal Income Fund (the "fund") for the period of November 1, 2025 to April 30, 2026.
Shareholder Report Annual or Semi-Annual Semi-Annual Shareholder Report
Additional Information [Text Block] You can find the fund’s prospectus, financial information on Form N‑CSR (which includes required tax information for dividends), holdings, proxy voting information, and other information atwww.troweprice.com/prospectus. You can also request this information without charge by contacting T. Rowe Price at 1‑800‑638‑5660 or info@troweprice.com or contacting your intermediary.
Material Fund Change Notice [Text Block]  
Additional Information Phone Number 1‑800‑638‑5660
Additional Information Email <span style="box-sizing: border-box; color: rgb(0, 0, 0); display: inline; flex-wrap: nowrap; font-size: 13.3333px; font-weight: 400; grid-area: auto; line-height: 17.3333px; margin: 0px; overflow: visible; text-align: justify; text-align-last: left; white-space-collapse: preserve-breaks;">info@troweprice.com</span>
Additional Information Website www.troweprice.com/prospectus
Expenses [Text Block]

What were the fund costs for the last six months? (based on a hypothetical $10,000 investment)

Table Summary
 
Costs of a $10,000 investment
Costs paid as a percentage of a $10,000 investment
Summit Municipal Income Fund - Advisor Class
$35
0.70%
Expenses Paid, Amount $ 35
Expense Ratio, Percent 0.70%
AssetsNet $ 2,585,498,000
Holdings Count | Holding 818
InvestmentCompanyPortfolioTurnover 8.50%
Additional Fund Statistics [Text Block]

What are some fund statistics?

Fund Statistics

Table Summary
Total Net Assets (000s)
$2,585,498
Number of Portfolio Holdings
818
Holdings [Text Block]

State Allocation (as a % of Net Assets)

Table Summary
Texas
11.6%
New York
8.6
California
8.3
Georgia
5.1
Maryland
4.8
Puerto Rico
4.7
Florida
4.1
District of Columbia
3.6
Virginia
3.3
Other
45.9
Largest Holdings [Text Block]

Industry Allocation (as a % of Net Assets)

Table Summary
Transportation
23.0%
Health Care
14.2
Special Tax
12.3
Housing
9.4
Education
7.9
General Obligations - State
6.0
General Obligations - Local
5.2
Water & Sewer
2.6
Leasing
2.2
Other
17.2
Material Fund Change [Text Block]
Updated Prospectus Web Address www.troweprice.com/paperless
C000211686  
Shareholder Report [Line Items]  
Fund Name Summit Municipal Income Fund
Class Name I Class
Trading Symbol PRIMX
Annual or Semi-Annual Statement [Text Block] This semi-annual shareholder report contains important information about Summit Municipal Income Fund (the "fund") for the period of November 1, 2025 to April 30, 2026.
Shareholder Report Annual or Semi-Annual Semi-Annual Shareholder Report
Additional Information [Text Block] You can find the fund’s prospectus, financial information on Form N‑CSR (which includes required tax information for dividends), holdings, proxy voting information, and other information atwww.troweprice.com/prospectus. You can also request this information without charge by contacting T. Rowe Price at 1‑800‑638‑5660 or info@troweprice.com or contacting your intermediary.
Material Fund Change Notice [Text Block]  
Additional Information Phone Number 1‑800‑638‑5660
Additional Information Email <span style="box-sizing: border-box; color: rgb(0, 0, 0); display: inline; flex-wrap: nowrap; font-size: 13.3333px; font-weight: 400; grid-area: auto; line-height: 17.3333px; margin: 0px; overflow: visible; text-align: justify; text-align-last: left; white-space-collapse: preserve-breaks;">info@troweprice.com</span>
Additional Information Website www.troweprice.com/prospectus
Expenses [Text Block]

What were the fund costs for the last six months? (based on a hypothetical $10,000 investment)

Table Summary
 
Costs of a $10,000 investment
Costs paid as a percentage of a $10,000 investment
Summit Municipal Income Fund - I Class
$18
0.36%
Expenses Paid, Amount $ 18
Expense Ratio, Percent 0.36%
AssetsNet $ 2,585,498,000
Holdings Count | Holding 818
InvestmentCompanyPortfolioTurnover 8.50%
Additional Fund Statistics [Text Block]

What are some fund statistics?

Fund Statistics

Table Summary
Total Net Assets (000s)
$2,585,498
Number of Portfolio Holdings
818
Holdings [Text Block]

State Allocation (as a % of Net Assets)

Table Summary
Texas
11.6%
New York
8.6
California
8.3
Georgia
5.1
Maryland
4.8
Puerto Rico
4.7
Florida
4.1
District of Columbia
3.6
Virginia
3.3
Other
45.9
Largest Holdings [Text Block]

Industry Allocation (as a % of Net Assets)

Table Summary
Transportation
23.0%
Health Care
14.2
Special Tax
12.3
Housing
9.4
Education
7.9
General Obligations - State
6.0
General Obligations - Local
5.2
Water & Sewer
2.6
Leasing
2.2
Other
17.2
Material Fund Change [Text Block]
Updated Prospectus Web Address www.troweprice.com/paperless