The Montgomery County, MD income tax rate is 3.20% of your Maryland taxable income. You don’t pay it to the county directly. The Comptroller of Maryland collects it on your state return and forwards the local share to Montgomery County, so the 3.20% appears as a line on Maryland Form 502 right after the state tax calculation.1Comptroller of Maryland. Tax Information for Individual Income Tax
What the 3.20% Applies To
The rate is applied to your Maryland taxable income, meaning the figure left after your deductions, exemptions, and any allowed modifications are subtracted from your Maryland adjusted gross income. Multiply that number by 0.032 and you have your Montgomery County liability for the year.
Maryland calls this a piggyback tax because the county has no separate collection machinery. Under Maryland Tax-General Section 10-106, every county must set a local rate somewhere between 2.25% and 3.30%.2Maryland General Assembly. Maryland Code Tax-General 10-106 – County Income Tax Rate Montgomery County sits near the top of that band at 3.20%, the same rate used by 13 of Maryland’s 23 counties plus Baltimore City.3Maryland Department of Legislative Services. 2026 Local Tax Rates Revenue funds public schools, transportation, public safety, and infrastructure.
Your Combined State and Local Tax
The 3.20% is stacked on top of Maryland’s state income tax, which uses a progressive bracket system running from 2% on the first $1,000 of taxable income up to 6.5% on income above $1,000,000 for single filers (or above $1,200,000 for joint filers).4Comptroller of Maryland. Maryland Income Tax Rates and Brackets That is why the combined bite feels heavy.
A single filer with $100,000 in Maryland taxable income owes roughly $4,697.50 in state tax, plus $3,200 to Montgomery County, for a combined bill around $7,897.50. The effective combined rate works out near 7.9%. A single filer earning $500,000 faces a combined marginal rate of 8.95% on income in that bracket (5.75% state plus 3.20% local), and high earners above $1,000,000 see a combined marginal rate of 9.7%.
Who Owes the Montgomery County Rate
You owe the 3.20% if you are a Maryland resident whose county of residence is Montgomery. Maryland uses two tests, and meeting either one makes you a resident:
- Domicile: You are domiciled in Maryland on the last day of the tax year. Domicile is the place you consider your permanent home and intend to return to when away.
- Statutory residency: You maintain a place of abode in Maryland for more than six months of the tax year and are physically present in the state for 183 days or more during that year.
Both conditions of the statutory test must be met together. Owning a home in Montgomery County on its own does not create tax liability if you spend fewer than 183 days in the state.5Maryland Comptroller of the Treasury. Administrative Release 37 – Domicile and Residency
If You Moved During the Year
Part-year residents prorate deductions, exemptions, and certain credits based on the share of total income attributable to the Maryland residence period, using the Maryland Income Factor Worksheet.6Comptroller of Maryland. Filing Information for Individual Income Tax For the local rate, Maryland looks at the county where you lived on the last day of your Maryland residency. If you moved from Montgomery to Howard County in August and stayed in Maryland, Howard’s rate applies for the year, not Montgomery’s.
Nonresidents Working in Maryland
If you live outside Maryland but earn income in the state, you don’t pay the Montgomery County 3.20%. Nonresidents pay a special flat local rate of 2.25% on top of Maryland state tax.1Comptroller of Maryland. Tax Information for Individual Income Tax
Commuting To DC Or Virginia
Cross-border commuting is common in Montgomery County, so reciprocity matters. Maryland has reciprocity agreements with the District of Columbia, Virginia, West Virginia, and Pennsylvania.7Maryland Comptroller of the Treasury. Maryland Income Tax Administrative Release No. 3 Wage and salary income is taxed only by your state of residence under those agreements.
If you live in Montgomery County and work in DC or Northern Virginia, you owe Maryland state tax and the 3.20% Montgomery County local tax on your wages, and you do not owe DC or Virginia income tax on them. File an exemption certificate with your employer so withholding goes to Maryland. One exception: except for West Virginia, the reciprocity agreements don’t apply if you maintain a place of abode in the other jurisdiction for more than six months and are physically present there for 183 days or more.7Maryland Comptroller of the Treasury. Maryland Income Tax Administrative Release No. 3 For income from a state without a reciprocity agreement, claim a credit on your Maryland return for taxes paid to that state so you aren’t taxed twice.
How To File And Pay
Montgomery County residents file Maryland Form 502, which covers state and local tax on one return.8Comptroller of Maryland. Individual Tax Forms and Instructions Nothing goes separately to the county. You enter your county code, and the 3.20% is applied to your Maryland taxable income.
Have your completed federal return, your W-2s and 1099s, and documentation for any Maryland-specific deductions or credits ready. Form 502 and its instructions are on the Comptroller’s website.9Comptroller of Maryland. 2025 Individual Income Tax Forms The Comptroller runs a free iFile portal for resident returns, and most commercial tax software supports Maryland filing.10Comptroller of Maryland. iFile Choose Form Entrance Paper filers mail Form 502 to the address in the instruction booklet. Payment can be made by direct bank withdrawal through the Comptroller’s online portal or by credit card through authorized processors, which charge a convenience fee of roughly 2% to 3%.
Estimated Payments
If you have income not subject to withholding, such as self-employment earnings, rental income, or investment gains, and you expect to owe more than $500 in Maryland tax after withholding, you must make quarterly estimated payments.11Maryland Comptroller of the Treasury. Personal Tax Tip 54 – Should You Pay Estimated Tax to Maryland That $500 threshold includes the local tax, so the 3.20% counts toward it.
Quarterly due dates for 2026:
- First quarter: April 15, 2026
- Second quarter: June 15, 2026
- Third quarter: September 15, 2026
- Fourth quarter: January 15, 2027
Use Maryland Form PV or the preprinted voucher included with your prior-year return. If a due date falls on a weekend or holiday, the deadline shifts to the next business day.
Extensions And Penalties
Maryland automatically extends your filing deadline if you have a federal extension; no separate state form is needed. The extension covers filing, not payment. If you owe, pay by the original April deadline or face penalty and interest.
Unpaid tax draws a 5% penalty plus interest from the original due date. An additional balance discovered after filing accrues interest at 6% per year until paid. Both the state and local portions carry these charges, so an underpayment on the Montgomery County share is not cost-free. Paying at least 90% of what you owe by April, or 110% of your prior-year liability through withholding and estimated payments, is the safest way to steer clear of underpayment penalties.
Deducting The Local Tax Federally
The Montgomery County income tax you pay is deductible on your federal return if you itemize on Schedule A, as part of the state and local tax (SALT) deduction that also covers Maryland state income tax and property taxes. The SALT deduction is capped at $40,000 for most filers ($20,000 if married filing separately). For taxpayers with modified adjusted gross income above $500,000, the cap phases down at 30 cents per dollar over the threshold, with a floor of $10,000.12Internal Revenue Service. Topic No. 503, Deductible Taxes
Many Montgomery County households, between state tax, the 3.20% local rate, and property taxes on expensive homes, hit or exceed the SALT cap. Anything above the cap gets no federal benefit, which is worth weighing when you decide between itemizing and the standard deduction.