coral reef, unincorporated territory of the United States in the Northern Line Islands, west-central Pacific Ocean. The reef is located about 920 miles (1,480 km) southwest of Honolulu. It is a barren atoll with a deep lagoon (5 by 9.5 miles 【8 by 15 km】 and has a land area of 0.01 square mile (0.03 square km). It was sighted in 1798 by an American, Edmund Fanning, and was named for another American, W. Kingman, who first described it in 1853. Formally annexed by the United States in 1922, it became a U.S. naval reservation in 1934. In 1937–38 the lagoon was used for commercial purposes as a station for seaplanes flying between Hawaii and Samoa. The U.S. Navy administered the reef until 2000, when responsibility was transferred to the U.S. Fish and Wildlife Service; the following year the reef was declared a U.S. National Wildlife Refuge. In 2009 it was designated part of the Pacific Remote Islands Marine national monument. Kingman Reef is uninhabited. It provides nesting grounds and other habitats for migratory seabirds and threatened sea turtles.