County · Maryland
St. Mary's County, Maryland
St. Mary's County, Maryland. St. Mary's County had 116,692 residents in 2025 by the Census Bureau's estimate, up 2.6% since 2020, faster than Maryland (+1.4%). It holds 11 places (1 city, village or borough and 10 census-designated) and 23 census tracts. GEOID 24037.
St. Mary's County is one of the 2 counties of the Lexington Park, MD metropolitan statistical area (the Census Bureau's July 2023 delineation).
Residents, July 2025 estimate
116,692
Census Bureau estimate (no margin published)
2020 Census count: 113,777 · ACS 2020-2024: 115,126
Median household income
$119,446
±$4,480 (90% margin)
Maryland: $103,678
Median home value
$407,600
±$8,365 (90% margin)
Maryland: $419,900
Median gross rent
$1,747
±$60 (90% margin)
Maryland: $1,705
How many people live in St. Mary's County, and is it growing?
The 2020 Census counted 113,777 residents in St. Mary's County. The Census Bureau estimates 116,692 for July 1, 2025, up 2.6% since 2020, faster than Maryland (+1.4%). The 2020-2024 American Community Survey puts the population at 115,126 over 359 square miles of land.
| Measure | St. Mary's County | Maryland | Change since 2015-2019 |
|---|---|---|---|
| Total population | 115,126 | 6,206,011 | +2,836 |
| Households | 42,436±536 | 2,362,928 | +1,884 |
| Average household size | 2.65±0.03 | 2.57 | −0.05 |
| Housing units | 46,385±56 | 2,560,784 | +1,276 |
St. Mary's County's population since 2000
From 86,211 in 2000 to 116,692 in 2025: up 35.4%. The 2000, 2010 and 2020 figures are census counts. The 2005 figure is the Census Bureau's intercensal estimate, revised to fit the 2000 and 2010 counts and drawn on 2010 boundaries; 2015 and 2025 are July 1 estimates made from the census before them.
Source: The 2000, 2010 and 2020 Census counts and the Census Bureau's population estimates (intercensal 2000-2010, Vintage 2020, Vintage 2025) · Census population estimates
Source: American Community Survey 2020-2024 5-year estimates, U.S. Census Bureau (released January 2026); PEP Vintage 2025 (CO-EST2025); 2020 Census · Check it at data.census.gov
What cities and towns are in St. Mary's County?
St. Mary's County holds 11 places: 1 city, village or borough (an incorporated place) and 10 census-designated places. The largest is Lexington Park with 13,252 residents (2020-2024). Places that cross a county line are listed with the share of their 2020 residents who live in this county.
| Lexington Park | 13,317 | $94,799 |
|---|---|---|
| California | 12,947 | $119,855 |
| Wildewood | 7,821 | $126,890 |
| Leonardtown | 4,563 | $153,819 |
| Golden BeachGEOID 2433850 | 3,651 | $133,194 |
| CallawayGEOID 2412175 | 1,779 | $160,341 |
| MechanicsvilleGEOID 2451800 | 1,673 | $120,966 |
| Charlotte HallGEOID 2415475 | 1,388 | $84,271 |
| Piney Point | 980 | $129,018 |
| Tall TimbersGEOID 2476675 | 451 | $195,982 |
| St. George IslandGEOID 2469425 | 265 | $250,000 or more |
Source: American Community Survey 2020-2024 5-year estimates, U.S. Census Bureau (released January 2026); 2020 place-by-county parts · Check it at data.census.gov
Who lives in St. Mary's County?
The median resident of St. Mary's County is 37.2 years old; 23.9% are under 18 and 14.0% are 65 or older. The largest group is non-Hispanic white residents at 70.3%, then non-Hispanic Black residents at 14.6%. 4.3% of residents were born outside the United States.
| Measure | St. Mary's County | Maryland | Change since 2015-2019 |
|---|---|---|---|
| Median age | 37.2±0.4 | 39.4 | no clear change |
| Under 18 years | 23.9%±0.1 pts | 22.2% | – |
| 65 years and over | 14.0%±0.1 pts | 16.7% | – |
| Hispanic or Latino (any race) | 6.1% | 12.5% | +0.9 pts |
| White alone, not Hispanic | 70.3%±0.6 pts | 46.6% | −3.8 pts |
| Black or African American alone, not Hispanic | 14.6%±0.5 pts | 28.9% | no clear change |
| Asian alone, not Hispanic | 2.6%±0.3 pts | 6.5% | no clear change |
| American Indian and Alaska Native alone, not Hispanic | 0.1%±0.1 pts | 0.1% | – |
| Native Hawaiian and Other Pacific Islander alone, not Hispanic | 0.0%±0.1 pts | 0.0% | – |
| Two or more races, not Hispanic | 5.9%±0.8 pts | 4.6% | – |
| Some other race alone, not Hispanic | 0.5%±0.3 pts | 0.7% | – |
| Born outside the United States | 4.3%±0.6 pts | 16.6% | no clear change |
| Speak a language other than English at home (age 5+) | 7.3%±1.0 pts | 21.1% | – |
| Civilian veterans (age 18+) | 14.4%±1.1 pts | 6.8% | – |
| With a disability | 11.9%±1.1 pts | 11.6% | – |
| No health insurance coverage | 3.9%±0.9 pts | 6.3% | no clear change |
| High school graduate or higher (age 25+) | 92.7%±1.1 pts | 91.1% | – |
| Bachelor's degree or higher (age 25+) | 36.5%±1.6 pts | 43.4% | +4.6 pts |
| Graduate or professional degree (age 25+) | 16.2%±1.3 pts | 20.8% | – |
| Moved from another state in the past year | 3.7%±0.8 pts | 2.6% | – |
Source: American Community Survey 2020-2024 5-year estimates, U.S. Census Bureau (released January 2026) (Data Profiles DP02, DP05) · Check it at data.census.gov
What do households in St. Mary's County earn?
Half of St. Mary's County's 42,436 households earn less than $119,446 a year (±$4,480), against $103,678 in Maryland. In 2015-2019 the median was $110,572 in 2024 dollars, so it rose by $8,874 after inflation. 8.0% of residents live below the poverty line.
| Measure | St. Mary's County | Maryland | Change since 2015-2019 |
|---|---|---|---|
| Median household income | $119,446±$4,480 | $103,678 | +$8,874 |
| Mean household income | $142,976±$4,914 | $136,642 | – |
| Per capita income | $53,417±$1,686 | $52,979 | +$3,754 |
| People below the poverty line | 8.0%±1.3 pts | 9.4% | no clear change |
| Children under 18 below the poverty line | 8.7%±2.5 pts | 11.5% | no clear change |
| Households receiving SNAP | 11.2%±1.5 pts | 11.2% | – |
| Households with a broadband subscription | 93.1%±1.1 pts | 92.4% | – |
Source: American Community Survey 2020-2024 5-year estimates, U.S. Census Bureau (released January 2026) (Data Profile DP03) · Check it at data.census.gov
What does housing cost in St. Mary's County?
Owners occupy 73.2% of St. Mary's County's occupied homes and renters 26.8%. The median owner-occupied home is valued at $407,600 by its owner (±$8,365). The median renter pays $1,747 a month including utilities, and 37.8% of renters pay 35% or more of their income on rent.
| Measure | St. Mary's County | Maryland | Change since 2015-2019 |
|---|---|---|---|
| Median home value (owner-occupied) | $407,600±$8,365 | $419,900 | +$36,792 |
| Median gross rent | $1,747±$60 | $1,705 | no clear change |
| Renters paying 35% or more of income on rent | 37.8%±4.9 pts | 42.3% | no clear change |
| Median monthly owner costs, with a mortgage | $2,268±$44 | $2,347 | – |
| Owner-occupied homes | 73.2%±1.8 pts | 67.6% | no clear change |
| Housing units | 46,385±56 | 2,560,784 | +1,276 |
| Homeowner vacancy rate | 1.4%±0.8 pts | 0.8% | – |
| Rental vacancy rate | 3.3%±1.9 pts | 4.7% | – |
| Single-family detached homes | 72.5%±1.8 pts | 51.2% | – |
| Mobile homes | 3.4%±0.7 pts | 1.3% | – |
| Built 2020 or later | 1.7%±0.5 pts | 1.4% | – |
| Built 1939 or earlier | 3.4%±0.7 pts | 10.7% | – |
Source: American Community Survey 2020-2024 5-year estimates, U.S. Census Bureau (released January 2026) (Data Profile DP04) · Check it at data.census.gov
How many new homes is St. Mary's County building?
Builders took permits for 282 new housing units across St. Mary's County in 2025 (264 single-family), 2.4 per 1,000 residents.
Source: Building Permits Survey, annual county files 2019-2025, U.S. Census Bureau · Census Building Permits Survey
How do people in St. Mary's County get to work?
72.2% of St. Mary's County's workers drive alone and 17.5% work from home. The average trip to work takes 29.9 minutes. The unemployment rate in 2020-2024 averaged 3.6%.
| Measure | St. Mary's County | Maryland | Change since 2015-2019 |
|---|---|---|---|
| In the labor force (age 16+) | 68.5%±1.3 pts | 67.1% | – |
| Unemployment rate | 3.6%±0.8 pts | 4.9% | no clear change |
| Drove alone to work | 72.2%±2.0 pts | 64.7% | – |
| Carpooled | 5.7%±0.9 pts | 7.7% | – |
| Public transportation | 0.9%±0.3 pts | 4.2% | – |
| Walked | 2.8%±0.8 pts | 2.0% | – |
| Worked from home | 17.5%±1.7 pts | 19.3% | +13.7 pts |
| Mean travel time to work | 29.9 min±1.1 | 31.1 min | −1.6 min |
Source: American Community Survey 2020-2024 5-year estimates, U.S. Census Bureau (released January 2026) (Data Profile DP03) · Check it at data.census.gov
What are St. Mary's County's census tracts?
St. Mary's County is divided into 23 census tracts. Among those with a reliable estimate, median household income runs from $74,019 (Tract 8759.03) to $186,223 (Tract 8761.02).
All 23 census tracts of St. Mary's County, with their figures
Source: American Community Survey 2020-2024 5-year estimates, U.S. Census Bureau (released January 2026) · Check it at data.census.gov
How does St. Mary's County compare with Maryland's other counties?
| Measure | Rank |
|---|---|
| Population | 12th of 24 |
| Growth 2020-2025 | 8th of 24 |
| Residents per square mile | 13th of 24 |
| Median household income | 7th of 24 |
| Median home value | 11th of 24 |
| Median gross rent | 8th of 24 |
| Poverty rate | 15th of 24 |
| Bachelor's degree or higher | 13th of 24 |
| Median age | 22nd of 24 |
Source: PlainCities ranks from the American Community Survey 2020-2024 5-year estimates, U.S. Census Bureau (released January 2026) and PEP Vintage 2025 · How ranks are computed
How these figures are made: methodology and release checks · reading a margin of error · every state · corrections
Not on this page: crime, weather and schools for St. Mary's County are other agencies' records. Crime: the FBI's Crime Data Explorer · climate: NOAA's U.S. Climate Normals · schools: the National Center for Education Statistics' school search.