The Mule Keys are a group of scattered islets in the Florida Keys in Monroe County, Florida, United States. They are between 3 and 12 mi (4.8 and 19.3 km) west of Key West, separated from it by the Northwest Channel. On the west, they are separated from the Marquesas Keys by the 6-mile (9.7 km) wide Boca Grande Channel. They belong to the outlying islands of the Florida Keys. Administratively, they are an unincorporated area of Monroe County. The islets are part of the Key West National Wildlife Refuge. The area of the islets totals 1.07 sq mi (2.8 km2), of which 1.02 sq mi (2.6 km2) are land area and 0.05 sq mi (0.13 km2) inland water bodies (on three of the keys). The islets are uninhabited except for Mule Key, for which the census of 2000 lists one housing unit with a population of two