St. Mary's County's estimated 2026 population is 117,168 with a growth rate of 0.41% in the past year according to the most recent United States census data. St. Mary's County is the 12th largest county in Maryland. The 2010 population was 105,772 and has seen a growth of 10.77% since that time.
Data after 2023 is projected based on recent change
Overall: 37.2 years
Female: 38.1 years
Male: 36.3 years
There are 87,577 adults, (16,144 of whom are seniors) in St. Mary's County.
Female: 57,072 (49.6%)
Male: 58,054 (50.4%)
The racial composition of St. Mary's County includes 71.29% White, 14.63% Black or African American, and smaller percentages for Asian, other race, Native American, Native Hawaiian or Pacific Islander and multiracial populations.
Race | Population | Percentage (of total) |
|---|---|---|
| White | 82,070 | 71.29% |
| Black or African American | 16,847 | 14.63% |
| Two or more races | 10,645 | 9.25% |
| Asian | 3,062 | 2.66% |
| Other race | 2,366 | 2.06% |
| Native American | 130 | 0.11% |
| Native Hawaiian or Pacific Islander | 6 | 0.01% |
St. Mary's County's average per capita income is $75,622. Household income levels show a median of $119,446. The poverty rate stands at 7.98%.
Name | Median | Mean |
|---|---|---|
| Married Families | $170,072 | - |
| Families | $141,221 | $162,257 |
| Households | $119,446 | $142,976 |
| Non Families | $73,545 | $89,014 |
Average Income
Median Household Income
Poverty Rate