Known as Forest Park Road, the state highway runs 1.11 miles (1.79 km) from MD 235 north to an entrance to Naval Air Station Patuxent River (NAS Patuxent River) within Lexington Park in eastern St. Mary's County.

MD 712 heads north as a two-lane undivided road through a forested area between residential subdivisions to the east and NAS Patuxent River to the west.

The state highway parallels the military base's perimeter road for much of its length.

Immediately after passing Pine Hill Run Road, the state highway reaches its northern terminus at an entrance to NAS Patuxent River.

The state highway was built as part of a 3-mile (4.8 km) project to improve MD 235 between Jarboesville (now Lexington Park) and the community of Hermanville and provide access to the South Gate of NAS Patuxent River.