The 607 islands constituting the four states include large, mountainous islands of volcanic origin and coral atolls. Kosrae is largely mountainous, with two peaks, Fenkol (634 m/2,080 ft) and Matanti (583 m/1,913 ft). Pohnpei contains a large volcanic island, with the highest elevation that of Mt. Totolom (791 m/2,595 ft). Truk contains 14 islands that are mountainous and of volcanic origin. Yap contains four large high islands, with the peak elevation that of Mt. Tabiwol (178 m/584 ft). The outer islands of all states are mostly coral atolls.