Island of Japan, located in the Ryukyu archipelago, in the East China Sea. The largest island in the Ryukyu chain, it is about 70 mi (112 km) long and 7 mi (11 km) wide, with an area of 466 sq mi (1,206 sq km). It was the site of severe fighting between the U.S. and Japan in World War II. In April 1945 U.S. troops made an amphibious landing there, which was heavily defended by the Japanese. In a three-month-long campaign, both sides sustained heavy casualties before U.S. forces gained control of the island. In 1972 the United States returned jurisdiction over Okinawa to Japan, though the U.S. military continued to maintain installations there.