COUNTY · MD
St. Mary's County, Maryland
St. Mary's County is a county in Maryland with FIPS code 24037 and an estimated population of 115,281 (Census 2023), 12th largest of 24 in the state.
County facts
- Name
- St. Mary's County
- State
- Maryland
- Type
- county
- FIPS code
- 24037
- State FIPS
- 24
- Population (2023)
- 115,281
- Change since 2020
- +1.1%
- State rank
- 12 of 24
Population is the Census Bureau’s Vintage 2023 estimate.
Questions
What is the FIPS code for St. Mary's County?
St. Mary's County, Maryland has the five-digit FIPS code 24037: 24 for the state and 037 for the county.
What state is St. Mary's County in?
St. Mary's County is in Maryland.
How do I know if an address is in this county?
Use the address lookup. ZIP codes and city names can cross county lines, so an address is the reliable check.
Sources: U.S. Census Bureau geographic reference files; Census Bureau Population Estimates, Vintage 2023. Last reviewed 2026-10-27.