The Line Islands, Teraina Islands or Equatorial Islands (Gilbertese: Aono Raina) are a chain of 11 atolls (with partly or fully enclosed lagoons, except Vostok and Jarvis) and coral islands (with a surrounding reef) in the central Pacific Ocean, south of the Hawaiian Islands. Eight of the atolls are parts of Kiribati. The remaining three—Jarvis Island, Kingman Reef, and Palmyra Atoll—are territories of the United States grouped with the United States Minor Outlying Islands. The Line Islands, all of which were formed by volcanic activity, are one of the longest island chains in the world, stretching 2,350 km (1,460 mi) from northwest to southeast. One of them, Starbuck Island, is near the geographic center of the Pacific Ocean (4°58′S 158°45′W / 4.97°S 158.75°W). Another, Kiritimati, has the largest land area of any atoll in the world. Only Kiritimati, Tabuaeran, and Teraina have a permanent population. Besides the 11 confirmed atolls and islands, Filippo Reef is shown on some maps, but its existence is doubted.