Jaluit (jäˈlōĭt) [key], atoll, c.40 mi (60 km) long and c.20 mi (30 km) wide, central Pacific, one of the Ralik Chain in the U.S. Marshall Islands. It comprises some 85 islets, of which Jaluit Island (4 sq mi/10.4 sq km) is the largest. In World War II it was the headquarters of the Japanese admiralty for the Marshall Islands. U.S. forces captured the atoll in 1944. Jaluit is a seaport and trade center for the Marshalls.