Pohnpei (formerly known as Ponape or Ascension, from Pohnpeian: "upon (pohn) a stone altar (pei)") is an island of the Senyavin Islands which are part of the larger Caroline Islands group. It belongs to Pohnpei State, one of the four states in the Federated States of Micronesia (FSM). Major population centers on Pohnpei include Palikir, the FSM's capital, and Kolonia, the capital of Pohnpei State. Pohnpei is the largest island in the FSM, with an area of 334 km (129 sq mi), and a highest point of 782 m (2,566 ft), the most populous with 36,832 people, and the most developed single island in the FSM.
Pohnpei is home to the megaliths and ruined city of Nan Madol, built of artificial islands off the island's eastern shore beginning in the 8th or 9th century. An important archaeological site, it was declared a national historic site in 1985.