Property tax in St. Mary's County, Maryland
In St. Mary's County, the property tax bill comes from the Office of the County Treasurer. The Tax Year 2026 bill is paid in 2 installments, and the next one is due December 31, 2026. You can look up and pay the bill on the county's own payment page. Taken from St. Mary's County's own pages, checked September 23, 2026.
The median property tax bill in St. Mary's County, Maryland is $3,424 a year, which is about 0.84% of the county's median home value of $407,600. That effective rate is lower than the typical Maryland county (0.9%) and higher than the national median (0.81%). These are American Community Survey 5-year estimates (2024); your own bill depends on your home's assessed value and any exemptions.
Who sends the property tax bill in St. Mary's County, and how do you pay it?
The bill comes from the Office of the County Treasurer. The value it is based on is set by a state agency, the Maryland State Department of Assessments and Taxation (SDAT), St. Mary's County assessment office, which is who to ask if the value looks wrong. For how to look up and pay the bill, go to the county's own payment information.
Maryland's SDAT, not the county, values every property and hears the first appeal; the county Treasurer only sends the bill and collects it. You must keep paying while an appeal is pending, and an overpayment is refunded afterward. Homes inside the Town of Leonardtown pay town tax as a separate line on the same county bill, not on a separate town bill. The county gives only one of its three senior credits to an account each year, choosing the most valuable, and the credits reduce only the county tax, not the state tax, fire and rescue taxes or fees. Apply by May 1 for a senior credit to appear on the July bill; applications approved by September 1 can still receive the credit for that year. A new house or improvement finished by the end of December gets a separate half-year bill, due March 31. Card payments online or by phone carry a 2.5% fee; payments from a checking account are free.
When are property taxes due in St. Mary's County?
For the Tax Year 2026 (July 1, 2026 to June 30, 2027) bill, St. Mary's County splits the bill into 2 payments, the first due September 30, 2026 and the last December 31, 2026. The next one due is the second semi-annual installment, on December 31, 2026. A payment made after its due date is charged a 3% county penalty plus interest of 1% a month, starting October 1 for an annual bill or first installment and January 1 for a second installment. Delinquent bills are mailed at the end of January, and property with unpaid prior-year taxes is offered at the county's online tax lien sale, held the first Friday of March.
| Payment | Due | Note |
|---|---|---|
| Annual bill, or first semi-annual installment | September 30, 2026 (passed) | A home listed as your principal residence is billed in two installments by default; you may instead pay the whole year by September 30. Commercial property assessed under $9,000,000 can also qualify for two installments; other property is billed annually, due September 30. If your mortgage company pays your taxes and you want to pay annually, you must tell it in writing before May 1. Partial payments are not accepted. Online and phone payments must be received by midnight Eastern time on the due date, and a mailed payment counts as paid on its postmark date. |
| Second semi-annual installment | December 31, 2026 | Applies only to bills on the semi-annual schedule. The second installment includes a service fee, 1.122% for Tax Year 2026, which you avoid by paying both installments by September 30. No reminder is mailed; pay with the second coupon on your original bill. |
From St. Mary's County's published schedule, checked September 23, 2026. If a date falls on a weekend or holiday, the county's own rules on the next business day apply.
Estimate the property tax on a home in St. Mary's County
Enter a home's market value for a ballpark at St. Mary's County's average effective rate of 0.84% (Census). The real bill depends on the home's assessed value, the millage where it sits and any exemptions.
Estimated property tax: $3,424 / year
Property tax in St. Mary's County at a glance
| Measure | Value |
|---|---|
| Median annual property tax | $3,424 |
| Median home value | $407,600 |
| Effective tax rate | 0.84% |
| Typical Maryland county rate | 0.9% |
| National median county rate | 0.81% |
Effective rate = median real estate taxes paid divided by median home value. Source: U.S. Census Bureau, American Community Survey 5-year estimates.
How does St. Mary's County compare in Maryland?
Among Maryland's 24 counties, St. Mary's County has the 19th highest effective property-tax rate: 18 rank higher and 5 rank lower. That is on the lower side for Maryland. Nationally, it ranks 1480th of 3135 US counties by effective rate. See every Maryland county ranked.
How much do homeowners in St. Mary's County actually pay?
The median is only the middle bill. Across St. Mary's County's 31,049 owner-occupied homes, 58.1% pay $3,000 or more a year in property tax, 81.3% pay at least $2,000, and 2.7% pay under $800. Another 4.9% report paying no property tax at all, which usually means an exemption covers the whole bill.
| Annual bill | Homes | Share |
|---|---|---|
| Under $800 | 823 | 2.7% |
| $800 to $1,499 | 1,373 | 4.4% |
| $1,500 to $1,999 | 2,077 | 6.7% |
| $2,000 to $2,999 | 7,218 | 23.2% |
| $3,000 or more | 18,049 | 58.1% |
| No property tax paid | 1,509 | 4.9% |
Owners with a mortgage pay a median of $3,436 and owners without one pay $3,397. That is within 10% either way, so in St. Mary's County paying off the house does not go with a noticeably different bill. Census table B25103.
How does the St. Mary's County property tax bill compare with local incomes?
The median property tax bill of $3,424 is about 2.4% of the median income of St. Mary's County homeowner households, $145,440 a year. That compares two middles, so a retiree in a long-held home can pay a far larger share. 73.2% of St. Mary's County's occupied homes are lived in by their owners; renters pay property tax too, just folded into rent.
Have property taxes gone up in St. Mary's County?
Yes. The median bill went from $2,923 in 2015-2019 to $3,424 in 2020-2024, a 17.1% rise. Over the same span the median home value moved 35.3%, from $301,300 to $407,600. Bills rose more slowly than values, which is what assessment caps and falling millage rates do: the county is taxing a smaller share of each home's worth.
Two Census ACS 5-year periods with no survey years in common, in each period's own dollars. A change counts only if it exceeds the combined 90% margin of error.
Property tax in counties next to St. Mary's County
St. Mary's County borders 6 counties, 2 of them across the state line.
| County | Effective rate | Median bill | Median home value |
|---|---|---|---|
| Charles County, MD | 1.01% | $4,339 | $428,500 |
| Dorchester County, MD | 0.94% | $2,456 | $262,400 |
| Somerset County, MD | 0.92% | $1,591 | $173,200 |
| Calvert County, MD | 0.84% | $3,885 | $460,200 |
| St. Mary's County, MD (this county) | 0.84% | $3,424 | $407,600 |
| Westmoreland County, VA | 0.6% | $1,628 | $269,600 |
| Northumberland County, VA | 0.47% | $1,645 | $346,800 |
How is a home assessed in St. Mary's County?
Maryland assesses homes at 100% of market value in every county, St. Mary's County included. How Maryland assesses and reappraises homes.
Is there a homestead exemption in St. Mary's County?
Not as an exemption. Maryland's Homestead Tax Credit caps how much your taxable assessment can rise each year: 10% for the state portion, and a cap each county and municipality sets between 0% and 10% for its own. That is the Maryland rule, and it applies in St. Mary's County. Maryland's exemptions and relief programs in full.
On top of the Maryland programs, St. Mary's County runs its own:
- County Senior Matching Tax Credit: For owners 70 or older on July 1 of the tax year who receive Maryland's Homeowners' Property Tax Credit, the county adds a credit equal to the state credit, up to the remaining tax bill; it comes through the county's consolidated senior tax credit application, must be applied for every year, and must be repaid if the home is sold during the tax year. Apply by September 1.
- County Senior "Cap" Tax Credit: Freezes the county portion of the tax bill at its level in the year the owner turns 70 or first applies after 70, for owners 70 or older on July 1 whose principal residence is in the county and whose taxable net income is $80,000 or less; the application must be filed every year. Apply by September 1.
- County Senior "65-10" Tax Credit: A 10% credit off the county portion of the tax bill for up to 5 years, for owners 65 or older on July 1 whose principal residence is assessed under $400,000, whose taxable net income is $80,000 or less, and who are retired active-duty military or have been on the deed for at least 40 years; the application must be filed every year. Apply by September 1.
How to appeal your St. Mary's County property assessment
In St. Mary's County you appeal to the Maryland SDAT, Supervisor of Assessments for St. Mary's County (first-level hearing before an assessor). The deadline: Within 45 days of the date on the assessment notice. A buyer whose purchase transferred after January 1 and before July 1 may appeal within 60 days of the transfer. In a year with no new notice, an owner may file a petition for review by the first working day after January 1. How to file. Checked September 23, 2026 against the official appeal rules.
How Maryland's appeal process works, including the next level if the first one turns you down.
Maryland rules from primary state sources, reviewed September 7, 2026; sources on the Maryland page.
Work out your own numbers
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How much house can I afford?
Your income, debts and down payment against the 28/36 rule lenders actually use, with St. Mary's County's tax rate to hand.
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Mortgage calculator
Monthly payment with principal, interest, tax and insurance, plus what an extra payment saves you.
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Maryland income tax
Brackets, standard deduction and what Maryland actually taxes.
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Sales tax in St. Mary's County
The other local tax: combined state and local rate for this county.
Sources
- Median real estate taxes paid and median home value for St. Mary's County, Maryland: U.S. Census Bureau, American Community Survey 5-year estimates (2020-2024), tables B25103, B25077, B25102, B25119 and B25003; the five-year comparison uses the 2015-2019 estimates. Neighboring counties: Census county adjacency file.