County Government offices are located at 23115 Leonard Hall Drive, Leonardtown MD 20650; phone: 301‑475‑4661.
St. Mary's County as Described in 1904 
This "mother county" dates back to 1634, and has an area of 360 square miles. It was named in honor of the saint whom the devout colonists took as their patron. It forms the extremity of the Southern Maryland peninsula, lying between the Potomac and Patuxent rivers, its lower eastern side bordering on the Chesapeake. Historic Point Lookout is at the wide mouth of the Potomac. St. Mary's touches no other county except Charles, the Patuxent making in between it and Calvert. There are highlands along the waterfront and lowlands in the interior. Some of the soil is sandy, with a clay subsoil, and productive loam is found in parts of the county. Half the cultivated land is occupied by tenants. Forest areas abound in white and red oak, poplar, sycamore, pine, and chestnut. Farms fronting on the bay and rivers are generally large, and vestiges of the old manorial life are numerous. Tobacco growing chiefly engages the attention of the farmers, and corn, wheat, and potatoes are also grown; much live stock of an excellent grade is raised. The construction of a railroad to Point Lookout, traversing the county, is often urged. St. Mary's only railroad, the Washington City and Potomac, runs from Brandywine, on the Pope's Creek Line in Lower Prince George's, through eastern Charles and into St. Mary's as far as Mechanicsville, twelve miles from Leonardtown, the county seat, located about midway of the county. Steamboats from Washington and Baltimore touch at points on the Potomac, and the Weems Line vessels from Baltimore ply the Patuxent. Leonardtown, named after the first Governor Calvert, is one of the most interesting ancient colonial towns of Maryland. Its population is 463. The site of St. Mary's city is fourteen miles southeast of the county seat, on St. Mary's river. A seminary for girls is established there, and at the tomb of Leonard Calvert a monument has been erected. Charlotte Hall Academy, above Mechanicsville, was established by legislative enactment in 1774, and its alumni include many famous Marylanders.