Yap or Wa′ab (Yapese: Waqab) is an island located in the Caroline Islands of the western Pacific Ocean, and a part of the Federated States of Micronesia. It is considered to be made up of four separate islands: Yap Island proper (MarbaQ), Tamil/Gagil, Maap (Yapese: Maap′), and Rumung. The three are contiguous though separated by water and are surrounded by a common coral reef. They are formed from an uplift of the Philippine Sea Plate, and are referred to as "high" islands as opposed to atolls. The land is mostly rolling hills densely vegetated. Mangrove swamps line much of the shore.