St. Mary's County Flag

St. Mary's County

State:
Maryland
County Seat:
Leonardtown

St. Mary's County's estimated 2025 population is 116,277 with a growth rate of 0.43% 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 9.93% since that time.

116,277
Total Population
324
Population Density (mi²)
12
Population Rank (State)
498 0.43%
Annual Population Growth

St. Mary's County Population

St. Mary's County Population

Data after 2023 is projected based on recent change

Demographics

The racial composition of St. Mary's County includes 72.31% White, 14.75% Black or African American, and smaller percentages for Asian, other race, Native American and multiracial populations.

Population by Race

Race
Population
Percentage (of total)
White82,70272.31%
Black or African American16,87414.75%
Two or more races9,4538.27%
Asian2,9352.57%
Other race2,2902%
Native American1180.1%

St. Mary's County Marital Status

OverallMalesFemales0%10%20%30%40%50%60%70%80%90%100%

Married

Widowed

Divorced

Separated

Never Married

Economics and Income Statistics

St. Mary's County's average per capita income is $72,426. Household income levels show a median of $114,580. The poverty rate stands at 7.45%.

Families: A family includes the owner or renter of the home along with everyone related to them - whether through birth, marriage, or adoption. This includes relatives like spouses, children, parents, siblings, grandparents, and any other family members.
Households: A household includes all the people who occupy a housing unit (such as a house or apartment) as their usual place of residence.
Non Families: A nonfamily household is either someone living alone or when the owner/renter lives with people they aren't related to, like roommates.
Name
Median
Mean
Married Families$159,358$178,750
Families$133,566$155,397
Households$114,580$138,624
Non Families$75,133$88,217

$72,426

Average Income

$114,580

Median Household Income

7.45%

Poverty Rate