The Marquesas Keys form an uninhabited island group about 20 miles (32 km) 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.
Satellite image of the Marquesas Keys
The total area, including the lagoon, measures 29.37 km2 (11.34 sq mi). The land area, according to the United States Census Bureau, is 6.58 km2 (2.54 sq mi) (exactly 6,579,703 m2), the water area 0.17 km2 (0.066 sq mi) (165,744 m2), giving a combined area of 6.75 km2 (2.61 sq mi) (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 24°34′19″N 82°07′10″W / 24°34′19″N 82°07′10″W / 24.57194; -82.11944.
The islands are part of the Florida Keys, separated from the rest of the Florida Keys, which are farther east, by the Boca Grande Channel, which is 6 miles (9.7 km) wide until Boca Grande Key, the westernmost of the Mule Keys. Only the Dry Tortugas are farther west, 36 miles (58 km) west of the Marquesas Keys.
The central lagoon is called Mooney Harbor. The northernmost key is the largest and has a strip of sandy beach free of mangrove. In the past it was known as "Entrance Key". It surrounds the lagoon in the north and east. Adjoining in the south are smaller keys such as Gull Keys, Mooney Harbor Key, and finally about four unnamed keys in the southwest corner of the group. Older charts show that two of these keys once were named "Button Island" and "Round Island".
Six miles (10 km) west of the Marquesas Keys is Rebecca Shoal.
The islands are best known for their excellent sport fishing.