is a town in and the county seat of St. Mary's County, Maryland, United States. The population was 1,896 at the 2000 census. Leonardtown is perhaps most famous for the national oyster-shucking championship that occurs annually at the St. Mary's County fairgrounds.
Historic Leonardtown includes both a large public high school and a Catholic high school, offices of the county government, and St. Mary's Hospital which serves the healthcare needs of the county. The College of Southern Maryland maintains a growing satellite campus within city limits. An upscale home development located in the Breton Bay area is just outside of town, notable for both its country club golf course and swimming pool.
Leonardtown's population is growing due to the town's proximity to Patuxent River Naval Air Station and the Washington, DC metro area. Several new ethnic restaurants and an upscale supermarket opened during 2006 and 2007. Two recently constructed hotels are open for business within city limits. An old order Mennonite farming community is a few miles to the northwest where community members sell furniture, crafts, produce, and other homemade/home grown products. The Leonardtown Wharf waterfront park opened as a public attraction for both locals and tourists in May of 2008.
According to the United States Census Bureau, the town has a total area of 3.1 square miles (8.0 km²), all of it land.