Population 115,126 · Census ACS 2020–24
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Population and households in St. Mary's County
Household size in St. Mary's County
| Period | St. Mary's County | Maryland | U.S. |
|---|---|---|---|
| 2006–10 | 2.77 | 2.68 | 2.68 |
| 2010–14 | 2.81 | 2.73 | 2.73 |
| 2015–19 | 2.72 | 2.74 | 2.71 |
| 2020–24 | 2.72 | 2.68 | 2.65 |
| Change | −0.06 | +0.01 | −0.03 |
Households in St. Mary's County average 2.72 people, about the same as the country as a whole (2.65). Household size has edged down from 2.77 in 2006–10, as it has nationally. Households are largest in the north and smallest in the southeast.
Household size: the average number of people living in each occupied home. Source: BestNeighborhood calculations from U.S. Census Bureau ACS 5-year block-group estimates (table B25010).
Median age in St. Mary's County
| Period | St. Mary's County | Maryland | U.S. |
|---|---|---|---|
| 2006–10 | 36.6 | 38.5 | 37.7 |
| 2010–14 | 37.5 | 39.3 | 38.6 |
| 2015–19 | 38.9 | 40.2 | 39.6 |
| 2020–24 | 38.4 | 40.6 | 40.1 |
| Change | +1.8 | +2.1 | +2.3 |
The median resident of St. Mary's County is 38.4 years old, a few years younger than the national median of 40.1. The median age has climbed from 36.6 in 2006–10, as it has nationally. Of Maryland's 24 counties, only two are younger.
Median age: the age that splits residents into two equal halves. Source: BestNeighborhood calculations from U.S. Census Bureau ACS 5-year block-group estimates (table B01002).
Single-parent households in St. Mary's County
| Period | St. Mary's County | Maryland | U.S. |
|---|---|---|---|
| 2006–10 | 12.0% | 12.5% | 12.3% |
| 2010–14 | 9.8% | 12.6% | 12.3% |
| 2015–19 | 10.8% | 11.7% | 11.6% |
| 2020–24 | 11.9% | 11.7% | 11.6% |
| Change | −0.1 pts | −0.9 pts | −0.6 pts |
Single-parent households are about as common in St. Mary's County as they are nationally: 11.9%, against 11.6%. St. Mary's County has a higher share of single-parent households than most Maryland counties.
Single-parent households: households where one adult with no spouse present lives with children under 18. Source: BestNeighborhood calculations from U.S. Census Bureau ACS 5-year block-group estimates (table B11003).
Housing in St. Mary's County
Renters in St. Mary's County
| Period | St. Mary's County | Maryland | U.S. |
|---|---|---|---|
| 2006–10 | 27.1% | 31.0% | 33.3% |
| 2010–14 | 27.4% | 32.9% | 35.6% |
| 2015–19 | 29.0% | 33.1% | 36.0% |
| 2020–24 | 26.8% | 32.4% | 34.8% |
| Change | −0.3 pts | +1.4 pts | +1.5 pts |
Most households in St. Mary's County own their homes; 26.8% rent, below the national share of 34.8%. About three in ten owners (29.7%) have paid off their mortgages, well below the national share of 39.8%. Rentals cluster in the east; owners are most common in the northwest.
Renters: occupied homes that are rented rather than owned. Source: BestNeighborhood calculations from U.S. Census Bureau ACS 5-year block-group estimates (table B25003).
Vacant homes in St. Mary's County
| Period | St. Mary's County | Maryland | U.S. |
|---|---|---|---|
| 2006–10 | 10.3% | 9.0% | 11.4% |
| 2010–14 | 10.5% | 8.9% | 11.4% |
| 2015–19 | 10.2% | 8.9% | 11.1% |
| 2020–24 | 9.6% | 7.1% | 9.6% |
| Change | −0.7 pts | −1.9 pts | −1.8 pts |
Just as many homes sit empty in St. Mary's County as nationally: 9.6%. The rate is higher than in Maryland as a whole (7.1%). Vacancy has edged down 0.7 points since 2006–10, mirroring the country.
Vacant homes: homes with no one living in them, including vacation homes and homes for sale or rent. Source: BestNeighborhood calculations from U.S. Census Bureau ACS 5-year block-group estimates (table B25002).
Age of homes in St. Mary's County
| Period | St. Mary's County | Maryland | U.S. |
|---|---|---|---|
| 2006–10 | 1986 | 1974 | 1974 |
| 2010–14 | 1987 | 1975 | 1975 |
| 2015–19 | 1989 | 1976 | 1977 |
| 2020–24 | 1993 | 1978 | 1980 |
| Change | +7 | +4 | +6 |
Much of the housing in St. Mary's County is relatively new: half of its homes were built after 1993, compared with 1980 for the U.S. as a whole. The median year built has moved up from 1986 in 2006–10, a sign of steady new building. The newest homes are mostly in the center, the oldest in the northwest. St. Mary's County has the newest homes of any Maryland county.
Age of homes: the year that splits the housing stock into older and newer halves. Source: BestNeighborhood calculations from U.S. Census Bureau ACS 5-year block-group estimates (table B25035).
Rent in St. Mary's County
| Period | St. Mary's County | Maryland | U.S. |
|---|---|---|---|
| 2006–10 | $1,171 | $1,249 | $965 |
| 2010–14 | $1,296 | $1,363 | $1,040 |
| 2015–19 | $1,410 | $1,576 | $1,213 |
| 2020–24 | $1,749 | $1,869 | $1,571 |
| Change | +$578 | +$620 | +$606 |
A typical rental in St. Mary's County costs $1,749 a month with utilities, above the national median of $1,571. Still, rents here are lower than in Maryland as a whole ($1,869). Rents are up $578 a month from 2006–10, a 49% rise, a slower climb than the nation's. The typical renter here spends 30.3% of household income on rent, just over the 30% mark often used to define affordable rent.
Rent: monthly rent plus the utilities renters pay themselves. Source: BestNeighborhood calculations from U.S. Census Bureau ACS 5-year block-group estimates (table B25064).
Education in St. Mary's County
Bachelor's degrees in St. Mary's County
| Period | St. Mary's County | Maryland | U.S. |
|---|---|---|---|
| 2006–10 | 28.0% | 36.3% | 28.4% |
| 2010–14 | 29.9% | 37.7% | 29.6% |
| 2015–19 | 31.9% | 40.5% | 32.1% |
| 2020–24 | 36.6% | 43.4% | 35.6% |
| Change | +8.6 pts | +7.1 pts | +7.2 pts |
More than a third of adults 25 and older in St. Mary's County (36.6%) hold at least a bachelor's degree, close to the national share of 35.6%. The share is lower than in Maryland as a whole (43.4%). The share with a degree is up 8.6 points from 2006–10, as it has nationally.
Bachelor's degrees: adults 25 and older with a bachelor's degree or higher. Source: BestNeighborhood calculations from U.S. Census Bureau ACS 5-year block-group estimates (table B15003).
High school graduates in St. Mary's County
| Period | St. Mary's County | Maryland | U.S. |
|---|---|---|---|
| 2006–10 | 89.1% | 88.0% | 84.9% |
| 2010–14 | 90.9% | 89.1% | 86.1% |
| 2015–19 | 89.6% | 90.2% | 87.7% |
| 2020–24 | 92.7% | 90.9% | 89.3% |
| Change | +3.5 pts | +2.9 pts | +4.3 pts |
About nine in ten adults in St. Mary's County have finished high school (92.7%), above the national rate of 89.3%. The share with a diploma has risen 3.5 points since 2006–10, as it has nationally.
High school graduates: adults 25 and older with a high school diploma, GED or more. Source: BestNeighborhood calculations from U.S. Census Bureau ACS 5-year block-group estimates (table B15003).
Jobs in St. Mary's County
| Period | St. Mary's County | Maryland | U.S. |
|---|---|---|---|
| 2006–10 | 4.7% | 6.5% | 8.1% |
| 2010–14 | 5.2% | 8.1% | 9.4% |
| 2015–19 | 3.2% | 5.1% | 5.6% |
| 2020–24 | 3.7% | 5.0% | 5.4% |
| Change | −1.0 pts | −1.5 pts | −2.7 pts |
Jobs have been easier to find in St. Mary's County than nationally: unemployment was 3.7%, against 5.4%. Unemployment is down 1.0 points from 2006–10, mirroring the country. Because the Census pools five years of responses (2020–24), these rates smooth over short swings and lag the current job market.
Unemployment: people looking for work as a share of everyone working or looking. Source: BestNeighborhood calculations from U.S. Census Bureau ACS 5-year block-group estimates (table B23025).
St. Mary's County compared with nearby counties
| County | Household size | Median age | Single parents | Renters | Vacant homes | Median year built | Median rent | Bachelor's degree | High school diploma | Unemployment |
|---|---|---|---|---|---|---|---|---|---|---|
| St. Mary's County | 2.72 | 38.4 | 11.9% | 26.8% | 9.6% | 1993 | $1,749 | 36.6% | 92.7% | 3.7% |
| King George County | 2.80 | 38.7 | 9.9% | 23.8% | 6.1% | 1999 | $1,501 | 35.5% | 92.1% | 3.3% |
| Stafford County | 3.10 | 37.4 | 9.6% | 19.5% | 5.2% | 1997 | $2,155 | 44.1% | 92.7% | 3.9% |
| Fredericksburg City | 2.31 | 33.5 | 10.4% | 60.3% | 6.1% | 1984 | $1,605 | 45.1% | 92.0% | 4.4% |
| Wicomico County | 2.54 | 37.4 | 12.8% | 37.7% | 8.8% | 1982 | $1,346 | 29.1% | 90.5% | 5.9% |
| Spotsylvania County | 2.82 | 39.0 | 10.8% | 19.9% | 6.6% | 1997 | $1,814 | 34.7% | 90.9% | 5.3% |
| Worcester County | 2.26 | 49.5 | 10.0% | 22.0% | 29.7% | 1986 | $1,366 | 35.3% | 93.7% | 6.7% |
| Orange County | 2.58 | 42.4 | 9.1% | 21.3% | 9.1% | 1991 | $1,515 | 29.1% | 90.9% | 2.9% |
| Culpeper County | 2.83 | 39.7 | 12.1% | 25.0% | 5.4% | 1992 | $1,461 | 27.4% | 87.1% | 2.6% |
| Madison County | 2.52 | 46.6 | 8.4% | 22.2% | 10.6% | 1981 | $1,206 | 27.2% | 89.1% | 4.8% |
| Greene County | 2.67 | 42.9 | 11.8% | 16.6% | 8.5% | 1993 | $1,284 | 31.8% | 91.2% | 1.9% |
All figures 2020–24.
Counties with similar populations: Berkeley County, WV · Blair County, PA · Comanche County, OK · Carroll County, GA · Rockwall County, TX · Sheboygan County, WI · Potter County, TX · Oswego County, NY · Ontario County, NY · Newton County, GA
About these numbers
Every figure on this page is a BestNeighborhood calculation from the Census Bureau's American Community Survey (ACS), built up from the Census block groups that make up St. Mary's County. Each ACS 5-year release pools five years of responses; this page shows the last 15 releases, 2006–10 through 2020–24. Neighboring releases share four of their five years, so they move gradually and small changes between them are within the survey's margin of error; in small places the lines can jump from one release to the next for the same reason. The maps show the same measures for each neighborhood, ranked against the whole country.
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