Ngulu Atoll is a coral atoll of three islands in the Caroline Islands in the Pacific Ocean, and forms a legislative district in Yap State in the Federated States of Micronesia. Ngulu extends for 36 kilometres (22 mi) by 22 kilometres (14 mi) with 18 reef segments enclosing a deep central lagoon of 382 square kilometres (147 sq mi). The eastern portion of the reef is deeply submerged. Its total land area of the nine islets is only 0.4 square kilometres (0.15 sq mi). Nugulu is located approximately 104 kilometres (65 mi) south-southwest of Yap and is the westernmost atoll in the Federated States of Micronesia.