Population
116,692
2025
+2.4% since 2020
Source: U.S. Census Bureau, Population Estimates Program (Vintage 2025), 2025. Resident population, July 1 estimate.
St. Mary's County had an estimated 116,692 residents in 2025, up 2.4% (2,700 more people) since 2020. That is faster than Maryland as a whole (+1.4%), and the 9th fastest growth of 24 counties in Maryland.
Data as of 2025 · updated
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116,692
2025
+2.4% since 2020
Source: U.S. Census Bureau, Population Estimates Program (Vintage 2025), 2025. Resident population, July 1 estimate.
+36
2025
0.3 per 1,000 residents
+26 in total, 2021–2025
Source: U.S. Census Bureau, Population Estimates Program (Vintage 2025), 2025. People moving in from other U.S. counties minus people moving out.
3.4%
2025
+0.3 pts since 2019
Source: U.S. Bureau of Labor Statistics, Local Area Unemployment Statistics, 2025. Annual average unemployment rate.
282
2025
−21.4% since 2021
2.4 per 1,000 residents
Source: U.S. Census Bureau, Building Permits Survey, 2025. Housing units authorized by building permits in the year.
$119,446
2020–24
+24.6% since 2016–20
Source: U.S. Census Bureau, American Community Survey 5-year estimates, 2020–24. American Community Survey 5-year estimate.
32,683
2023
−1.2% since 2018
Source: U.S. Census Bureau, County Business Patterns, 2023. Paid employees of private employers in mid-March (County Business Patterns).
Net domestic migration added 36 people in 2025: more people moved in from other U.S. counties than moved out.
Private employers had 32,683 paid employees in mid-March 2023, −1.2% since 2018 (County Business Patterns).
Unemployment averaged 3.4% in 2025, 0.3 points higher than in 2019 (before the pandemic).
Builders were authorized to start 282 new homes in 2025, or 2.4 per 1,000 residents.
Median household income was $119,446 in the 2020–24 American Community Survey, +24.6% since 2016–20.
Across the 3,107 U.S. counties with a comparable estimate, its population growth ranks 1,163rd.
Part of the Lexington Park, MD metro area.
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| Year | Population | Change |
|---|---|---|
| 2025 | 116,692 | +476 |
| 2024 | 116,216 | +974 |
| 2023 | 115,242 | +401 |
| 2022 | 114,841 | +274 |
| 2021 | 114,567 | +575 |
| 2020 | 113,992 | – |
Census Bureau population estimates, July 1 of each year.
St. Mary's County grew by 2,700 people since 2020; the largest part came from natural change (+1,886).
| Component | 2025 | 2020–25 | Share |
|---|---|---|---|
| Natural changebirths minus deaths | +368 | +1,886 | |
| International migrationfrom and to other countries | +61 | +730 | |
| Domestic migrationfrom and to other U.S. counties | +36 | +26 | |
| Census adjustmentbalancing residual | +11 | +58 | |
| Total change | +476 | +2,700 |
Census Bureau population estimates, components of change, each year July 1 to June 30. The components add up to the change in the estimate; the Census adjustment is the small balancing figure the Bureau publishes.
| Measure | In Maryland | Among U.S. counties |
|---|---|---|
| Population growth | 9th of 24 | 1,163rd of 3,107 |
| Net domestic migration per 1,000 residents | 14th of 24 | 1,866th of 3,108 |
| Private-sector job growth | 19th of 24 | 2,032nd of 3,092 |
| Median household income | 7th of 24 | 56th of 3,107 |
| Lowest unemployment rate | 4th of 24 | 797th of 3,108 |
| New homes permitted per 1,000 residents | 10th of 24 | 1,350th of 3,005 |
1st = highest (lowest for unemployment). Counties are ranked only against others with a figure for the same period.
The County Growth and Demographics Report for St. Mary's County, MD as a PDF, from federal data: population and migration, housing and rents, permits, private employers and jobs, unemployment, ranks in the state and the country, and neighbouring counties, with a source next to every number. Pay once, no subscription.
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Over 2020–25, St. Mary's County's population change (+2.4%) was ahead of 2 of its 6 neighbouring counties and behind 4.
2 of its 6 neighbouring counties had a higher median household income than St. Mary's County's $119,446 (2020–24).
| County | Population2025 | Population change2020–25 | Net domestic migration per 1,000 residents2025 | Homes permitted per 1,000 residents2025 | Median household income2020–24 |
|---|---|---|---|---|---|
| St. Mary's County, MD This county | 116,692 | +2.4% | 0.3 | 2.4 | $119,446 |
| Westmoreland County, VA | 19,715 | +6.5% | 23.8 | 10.9 | $63,398 |
| Calvert County, MD | 94,484 | +1.7% | −1.3 | 1.7 | $133,922 |
| Northumberland County, VA | 12,557 | +6.1% | 21.3 | 5.2 | $66,480 |
| Charles County, MD | 176,593 | +5.9% | 9.3 | 5.3 | $122,816 |
| Dorchester County, MD | 33,628 | +3.4% | 14.7 | 1.9 | $61,839 |
| Somerset County, MD | 24,973 | +1.7% | 10.5 | 1.4 | $64,943 |
Census Bureau population estimates and building permits, American Community Survey 5-year income. Rates per 1,000 residents. – means no figure, or a base too small for a change or rate (it would swing on a few people). A figure from another period shows its year and is left out of the comparison.
Yes. Its population grew 2.4% between 2020 and 2025, about 2,700 more people (Census Bureau population estimates). Maryland as a whole changed +1.4% over the same years. That ranks 9th of 24 counties in Maryland for population growth.
On net, about 36 people in 2025: that many more moved in from other U.S. counties than moved out (Census Bureau net domestic migration estimate).
It averaged 3.4% in 2025 (BLS Local Area Unemployment Statistics, annual average).
About 116,692 people, according to the U.S. Census Bureau's population estimate for July 1, 2025.
Private employers there had 32,683 paid employees in mid-March 2023, −1.2% since 2018 (Census Bureau County Business Patterns; government jobs and the self-employed are not counted).
Map, parcel and listing layers cover North and South Carolina only for now. This page and the other Maryland county pages carry the public federal growth figures.
Email me when St. Mary's County gets new Census numbers: population, building permits, jobs and income. About 4 emails a year, one click to stop.
Each number shows its own period. Changes compare the latest period with five years earlier (or the earliest period available). Beacon CRE last refreshed these figures on 2026-11-05. Figures come from public federal statistics and are informational only, not investment advice. Check the source before relying on a number. Methodology: how we compute every number. More on every layer: data sources and licences.
Jobs outside North and South Carolina use County Business Patterns (paid private-sector employees in mid-March); wages and government jobs are not included.