12th most populous of 24
With 116,469 residents in 2024, St. Mary's County ranks 12th by population among Maryland's 24 counties and is home to 1.9% of the state's residents.
St. Mary's County is home to 116,469 people (2024 estimate) on 359 square miles of land. This page brings together official U.S. Census Bureau population estimates since 2000, the components of change—births, deaths and migration—American Community Survey indicators on income, housing, poverty and education, BEA economic accounts and BLS unemployment.
Key indicators
Population
116,469
July 1, 2024 estimate
2020 Census base
113,778
April 1, 2020
Change since 2020
+2.4%
2020–2024
Land area
359 mi²
929 km²
Population density
324.8 /mi²
2024 estimate ÷ land area
Births
1,374
Year to July 1, 2024
Deaths
1,011
Year to July 1, 2024
Natural change
+363
Births minus deaths, 2024
Net migration
+630
Domestic + international, 2024
Per capita personal income
$73,314
BEA, 2024
Gross domestic product
$10.4 billion
BEA, current dollars, 2024
Median household income
$119,446
ACS 2020–2024 5-year
Poverty rate
8.0%
ACS 2020–2024 5-year
Bachelor’s degree or higher
36.5%
Age 25+, ACS 2020–2024 5-year
Foreign-born residents
4.3%
ACS 2020–2024 5-year
Median home value
$407,600
ACS 2020–2024 5-year
Unemployment rate
2.9%
BLS annual average, 2024
Historical data
Pick an indicator to see its long-run evolution.
Population
2000–2024116,469▲ 35%
U.S. Census Bureau: intercensal estimates 2000–2009, Vintage 2020 (2010–2019) and Vintage 2024 (2020–2024), July 1.
Data summary
| Indicator | Value | Year and source |
|---|---|---|
| Population estimate | 116,469 | 2024 · U.S. Census Bureau |
| Population, 2010 Census | 105,151 | 2010 · U.S. Census Bureau |
| Population, 2000 | 86,498 | July 1, 2000 · Census intercensal |
| Change since 2000 | +34.6% | 2000–2024 · Census |
| International migration | +214 | 2024 · Census Vintage 2024 |
| Domestic migration | +416 | 2024 · Census Vintage 2024 |
| Birth rate | 11.8 per 1,000 | 2024 · calculated |
| Death rate | 8.7 per 1,000 | 2024 · calculated |
| Population rank in Maryland | 12th of 24 | 2024 · calculated |
| Per capita personal income | $73,314 | BEA, 2024 · official |
| Gross domestic product | $10.4 billion | BEA, current dollars, 2024 · official |
| Median household income | $119,446 | ACS 2020–2024 5-year · official |
| Poverty rate | 8.0% | ACS 2020–2024 5-year · official |
| Bachelor’s degree or higher | 36.5% | Age 25+, ACS 2020–2024 5-year · official |
| Foreign-born residents | 4.3% | ACS 2020–2024 5-year · official |
| Median home value | $407,600 | ACS 2020–2024 5-year · official |
| Median gross rent | $1,747/month | ACS 2020–2024 5-year · official |
| Median age | 37.2 years | ACS 2020–2024 5-year · official |
| Households | 42,436 | ACS 2020–2024 5-year · official |
| Owner-occupied homes | 73.2% | ACS 2020–2024 5-year · official |
St. Mary's County in context
Comparable indicators for St. Mary's County, Maryland and the United States.
| Indicator | County | Maryland | U.S. | Reference |
|---|---|---|---|---|
| Population change 2020–2024 | +2.4% | +1.3% | +2.6% | Census Vintage 2024 |
| Birth rate (per 1,000) | 11.8 | 10.5 | 10.6 | 2024 |
| Death rate (per 1,000) | 8.7 | 8.6 | 9.1 | 2024 |
| Net migration rate (per 1,000) | 5.4 | 5.5 | 8.2 | 2024 |
| Population density (/mi²) | 324.8 | 645.0 | 96.3 | 2024 |
| Per capita personal income | $73,314 | $79,259 | $73,204 | BEA, 2024 |
| Median household income | $119,446 | $103,678 | $80,734 | ACS 2020–2024 5-year |
| Poverty rate | 8.0% | 9.4% | 12.5% | ACS 2020–2024 5-year |
| Bachelor’s degree or higher | 36.5% | 43.4% | 35.7% | Age 25+, ACS 2020–2024 5-year |
| Foreign-born residents | 4.3% | 16.6% | 14.1% | ACS 2020–2024 5-year |
| Median home value | $407,600 | $419,900 | $332,700 | ACS 2020–2024 5-year |
| Median gross rent | $1,747/month | $1,705/month | $1,413/month | ACS 2020–2024 5-year |
| Median age | 37.2 years | 39.4 years | 38.9 years | ACS 2020–2024 5-year |
| Owner-occupied homes | 73.2% | 67.6% | 65.2% | ACS 2020–2024 5-year |
Did you know? St. Mary's County
A quarter century of change
Its population went from 86,498 in 2000 to 116,469 in 2024, a change of +34.6%, compared with +17.9% for Maryland as a whole.
Births and deaths
In the year to July 2024 the county recorded 1,374 births and 1,011 deaths, so births outnumbered deaths by 363.
Record population
Annual Census estimates since 2000 put the county's highest population in 2024, at 116,469.
13th in density
St. Mary's County has about 324.8 residents per square mile of land, ranking 13th of 24 counties; Maryland averages 645.0.
Household income rank
With a median household income of $119,446 (ACS 2020–2024 5-year), the county ranks 7th of 24 Maryland counties; the state median is $103,678.
Size of the economy
Its economy produced $10.4 billion of GDP in 2024 (BEA), 9th largest among 24 Maryland counties.
Latest economic growth
Real GDP grew 2.8% in 2024, adjusted for inflation (BEA, chained 2017 dollars).
Sources and methodology
- U.S. Census Bureau — County population totals and components, Vintage 2024
- U.S. Census Bureau — County estimates 2010–2020
- U.S. Census Bureau — Intercensal estimates 2000–2010
- U.S. Census Bureau — Gazetteer files (land area)
- U.S. Census Bureau — American Community Survey 2020–2024 5-year
- U.S. Bureau of Economic Analysis — Regional economic accounts
- U.S. Bureau of Labor Statistics — LAUS