The seat of historic
St. Mary's County, the Leonardtown area dates back to 1637, although it wasn't given its current name until 1728, and not incorporated until 1858. An annual October event is the St. Mary's County Oyster Festival, including a shucking competition. Leonardtown lies at the head of Breton Bay off Hwy 5 on Washington Street. Patuxent River Naval Air Station is nearby.