St. Mary's County Regional Airport (IATA: LTW, FAA LID: 2W6), also known as Captain Walter Francis Duke Regional Airport, is a public airport located in St. Mary's County, Maryland, United States, four miles (six km) northeast of the central business district of Leonardtown. The airport is also located 8 nmi (15 km) west of Naval Air Station Patuxent River. It is owned and operated by the St. Mary's County Board of County Commissioners.