The
Marquesas Keys form an uninhabited island group about west of
Key West, 4 miles (6 km) in diameter, and largely covered by
mangrove forest. They are an
unincorporated area of
Monroe County, Florida and belong to the Lower Keys
Census County Division. They are protected as part of the
Key West National Wildlife Refuge. The Marquesas were used for target practice by the military as recently as 1980. The total area, including the
lagoon, measures . The land area, according to the
United States Census Bureau, is (exactly 6,579,703 m²), the water area (165,744 m²), giving a combined area of (6,745,447 m²), not counting water areas with connection to the open sea, but including small landlocked lakes on the Keys. The group is located at coordinates .