Known for most of its length as Great Mills Road, the state highway runs 3.35 miles (5.39 km) from MD 5 in Great Mills east to the entrance to Naval Air Station Patuxent River (NAS Patuxent River) just east of the highway's intersection with MD 235 in Lexington Park.

The state highway originally extended east onto the Cedar Point peninsula from its present terminus in Lexington Park (previously known as Jarboesville) to the hamlet of Pearson's Corner, then north to Millstone Landing.

[4] Millstone Landing was the location of a ferry across the Patuxent River to the southern terminus of MD 2 in Solomons in Calvert County between 1933 and at least 1940.

[10] Following the entry of the U.S. into World War II, the U.S. Navy seized much of the Cedar Point peninsula to construct NAS Patuxent River in 1942.

The remainder of MD 246 from the naval air station to Great Mills was reconstructed with a bituminous concrete surface in 1944 to better connect the military base with Leonardtown.