Property tax in St. Mary’s County, Maryland is billed at a county rate of $0.8478 per $100 of assessed value for fiscal year 2027, unchanged from the prior year. On top of that, Maryland adds a state rate of $0.1120 per $100, and most properties carry a fire district tax that varies by location. The Maryland State Department of Assessments and Taxation (SDAT) sets your property’s assessed value; the St. Mary’s County Treasurer’s Office sends the bill and collects payment.1St. Mary’s County, Maryland. Office of the County Treasurer
On a home assessed at $300,000, the county portion alone comes to roughly $2,543 a year ($0.8478 × 3,000). Add the state rate and your fire district rate to estimate the full bill.
What Makes Up the Bill
Your tax is calculated by multiplying your assessed value (per $100) by each applicable rate. Several layers stack:
- County tax of $0.8478 per $100, set each year by the Commissioners of St. Mary’s County during the budget process.2St. Mary’s County Government. St. Mary’s County Government – FY2027 Budget
- State tax of $0.1120 per $100, set by Maryland.3Maryland Department of Assessments and Taxation. 2025-2026 Tax Rates and Homestead Credit Caps
- Fire district tax, which funds local volunteer fire departments and has historically ranged from about $0.024 to $0.056 per $100 depending on your district.
- Leonardtown municipal tax of approximately $0.12 per $100 if your property sits inside the town limits, on top of the county and state rates.
Your bill may also carry an Environmental Services Fee for waste and recycling.
When Payment Is Due
The tax year runs July 1 through June 30, and bills go out at the start of the cycle.4St. Mary’s County Government. Tax Year – Real Property If the property is your principal residence, you’re on a semi-annual schedule by default: the first installment is due September 30 and the second December 31, with no interest or penalty if paid on time. You can elect to pay the full amount annually instead.5New York Codes, Rules and Regulations. Maryland Code Tax-Property 10-204.3 – Semiannual Payment Schedules If your mortgage lender escrows, the servicer pays semi-annually unless you’ve directed it in writing to pay annually.
You can mail a check or money order to the address on the bill, use the drop box at the Treasurer’s Office, or pay online. Credit card payments through the portal typically carry a convenience fee around 2.5%, so e-check is the cheaper electronic route. After paying online, download the confirmation and check your account on the county’s tax bill lookup page within a few business days.6St. Mary’s County, Maryland. Office of the County Treasurer – Taxes
What Happens If You Pay Late
Maryland’s default interest rate on overdue property taxes is two-thirds of one percent per month, but St. Mary’s County has authority under state law to set its own rate and may apply different rates to commercial and noncommercial property.7Maryland General Assembly. Maryland Code Tax-Property 14-603 – Penalties and Interest Check your bill or call the Treasurer’s Office for the rate in effect. Interest starts the month after the due date and compounds.
If the bill stays unpaid, the county sells the delinquent lien at a public auction held on the first Friday of March for the preceding tax year’s delinquent accounts.8St. Mary’s County, Maryland. Annual Tax Sale Auction At least 30 days before advertising, the Treasurer mails the owner a notice. The property is then listed in a local newspaper for four consecutive weeks before the sale. The winning bidder receives a certificate of sale. You have a redemption window to pay off the lien plus interest; if you don’t redeem within two years, the certificate holder can file to foreclose your right of redemption and take the property.9Maryland Department of Assessments and Taxation. Office of the State Tax Sale Ombudsman
Credits That Can Lower Your Bill
Most of these credits require an application with a specific deadline. Waiting for the bill to arrive is usually too late.
Homestead Tax Credit
The Homestead Tax Credit caps how much your taxable assessment can rise in a year, no matter how much the market value jumped. Maryland law requires every county to set the cap at 10% or less.10Maryland Department of Assessments and Taxation. Maryland Homestead Property Tax Credit Program It applies only to your principal residence and requires a one-time application with SDAT. File it once and it stays in place for as long as you own and live there. Skip the application and you never get the credit, even if you qualify.
Homeowners’ Property Tax Credit
This is an income-based state credit for homeowners whose property tax is large relative to their income. Combined gross household income must be $60,000 or less. The deadline for the 2026 credit is October 1, and the calculation uses your 2025 income.11Maryland OneStop. Homeowners Property Tax Credit Application Form HTC 2026 You have to reapply every year.
St. Mary’s County Senior Tax Credit
Homeowners aged 65 and older can claim a county credit worth 10% of their county tax liability for up to five years. It requires an annual application and is separate from the state’s income-based credits, so qualifying for one doesn’t affect the other.
Disabled Veteran Property Tax Credit
Veterans with a permanent service-connected disability rating of at least 50% from the U.S. Department of Veterans Affairs may qualify for a credit on their home. The credit equals 25% of the county property tax for ratings between 50% and 74%, and 50% for ratings of 75% or higher. Federal adjusted gross income must be $100,000 or less, and the home must be owned by the veteran.12New York Codes, Rules and Regulations. Maryland Code Tax-Property 9-265 – Dwelling House Owned by Disabled Veteran Veterans with a nonpermanent 100% rating also qualify.
If You Think Your Assessment Is Too High
SDAT reassesses every property on a three-year cycle and mails a Notice of Assessment showing the new value. You have 45 days from the date on that notice to appeal.13Maryland Department of Assessments and Taxation. Assessment Appeal Process Any increase is phased in equally over three tax years; decreases take effect immediately.
The appeal has three levels, and each gives you a fresh shot at no cost. The first is an informal hearing with an assessor at the Supervisor’s office, where you learn how the value was set and present anything that counters it. If you disagree with that result, you have 30 days to appeal to the Property Tax Assessment Appeals Board (PTAAB). From there, you have another 30 days to take it to the Maryland Tax Court, which hears the case de novo and starts fresh without regard to the earlier decisions.
The burden of proof is on you, so evidence decides these cases. A recent independent appraisal, a list of comparable sales in your neighborhood, or photos of structural problems or adverse nearby conditions carry weight. Arriving with only the complaint that the number feels too high is the weakest version of an appeal.