Kingman Reef, uninhabited reef, less than 1 sq mi (2.6 sq km), central Pacific, one of the Line Islands, 1,075 mi (1,730 km) SW of Honolulu. It was discovered by Americans in 1798 and annexed by the United States in 1922. Formerly an airport on the route from Honolulu to Pago Pago, Kingman Reef is now under the jurisdiction of the U.S. navy.