ST. MARY'S COUNTY, MARYLAND
Origin: What would become St. Mary's County was land where the Conoy Indians lived. Here, the settlement of Lord Baltimore's Maryland began with the arrival of the passengers who had set sail on the Ark and the Dove from Cowes, England, on November 22, 1633. They landed at St. Clement's Island in the Potomac River on the southwestern side of present-day St. Mary's County on March 25, 1634. The date of their landing is commemorated annually as Maryland Day.
Established in 1637 (probably by an order of the Governor), St. Mary's, the first Maryland county, was named in honor of Mary, the mother of Jesus.
Boundaries: Bounded north & west by Charles County & Wicomico River; northeast by Chesapeake Bay & Patuxent River; south & southwest by Potomac River.
County Code
County Seat: Leonardtown, MD 20650
Form of Government: County Commissioners
Population: 1990 census: 75,974; 2000 census: 86,211; 2010 census: 105,151; 2020 census: 113,777
Courthouse, 41605 Court House Drive, Leonardtown, Maryland, November 2017. Photo by Diane F. Evartt.
Bays
Creeks
Islands
Lakes
Maps
Museums
Breton Bay in distance, Society Hill Road, Leonardtown, Maryland, April 2018. Photo by Diane F. Evartt.
websites:
Aging & Human Services Dept.: www.stmaryscountymd.gov/aging/
Airport: www.stmaryscountymd.gov/dpw/Airportinfo/
Animal Control: www.stmaryscountymd.gov/ES/AnimalControl/
Appeals, Board of: www.stmaryscountymd.gov/Boards/1/
Building Services: www.stmaryscountymd.gov/dpw/BuildingServicesOverview/
Circuit Court: www.mdcourts.gov/clerks/stmarys
College of Southern Maryland (Leonardtown campus): www.csmd.edu/about/locations/leonardtown-campus/
Corrections Division: www.firstsheriff.com/Corrections
County Administrator: www.stmaryscountymd.gov/CountyAdmin/
County Attorney: www.stmaryscountymd.gov/countyattorney/
County Commissioners: www.stmaryscountymd.gov/csmc/
County Government: www.stmaryscountymd.gov
County Government Directory: www.stmaryscountymd.gov/contactdirectory/
County Treasurer: www.stmaryscountymd.gov/treasurer/
District Court: www.mdcourts.gov/district/directories/courtmap.html#STMARYS
Economic Development Dept.: www.yesstmarysmd.com
Elections Board: www.stmaryscountymd.gov/supervisorofelections/
Emergency Services & Technology Dept.: www.stmaryscountymd.gov/ES/
Ethics Commission: www.stmaryscountymd.gov/Boards/24/
Finance Dept.: www.stmaryscountymd.gov/Finance/
Geographic Information Systems: www.stmaryscountymd.gov/IT/GIS/
Health Dept.: www.smchd.org
Housing Authority: www.stmaryshousing.org
Human Resources Dept.: www.stmaryscountymd.gov/hro/
Information Technology: www.stmaryscountymd.gov/IT/
Job Service: www.dllr.state.md.us/county/smd/
Land Use & Growth Management Dept.: www.stmaryscountymd.gov/lugm/
Library: www.stmalib.org
Public Information Office: www.stmaryscountymd.gov/pio/
Public Schools: www.smcps.org
Public Works & Transportation Dept.: www.stmaryscountymd.gov/dpw/
Recreation & Parks: www.stmaryscountymd.gov/recreate/
Recycling: www.stmaryscountymd.gov/dpw/Recycleprograms/
St. Mary's County Library System, 23250 Hollywood Road, Leonardtown, Maryland, November 2017. Photo by Diane F. Evartt.
Register of Wills: www.registers.maryland.gov/main/stmarys.html
St. Mary's County: www.stmaryscountymd.gov
Sheriff's Office: www.firstsheriff.com
Social Services Dept.: https://dhs.maryland.gov/local-offices/st-marys-county/
State's Attorney: www.stmaryscountymd.gov/sao/
Tourism Division: www.visitstmarysmd.com
University System of Maryland at Southern Maryland: https://usmsm.umd.edu/
Search the Manual
e-mail: mdmanual@maryland.gov
� Copyright August 19, 2026 Maryland State Archives