Ulithi (Yapese: Wulthiy, Yulthiy, or Wugöy) is an atoll in the Caroline Islands of the western Pacific Ocean, about 191 km (103 nautical mi) east of Yap. It consists of 40 islets totalling 4.5 km2 (1.7 sq mi), surrounding a lagoon about 36 km (22 mi) long and up to 24 km (15 mi) wide—at 548 km2 (212 sq mi) one of the largest in the world. It is administered by the state of Yap in the Federated States of Micronesia. Ulithi's population was 773 in 2000.