天皇海山群
Midway Atoll is part of a chain of volcanic islands, atolls, and seamounts extending from the Island of Hawaii up to the tip of the Aleutian Islands and known as the Hawaiian–Emperor seamount chain. It consists of a ring-shaped barrier reef nearly in diameter and several sand islets. The two significant pieces of land, Sand Island and Eastern Island, provide a habitat for millions of seabirds. The island sizes are shown in the table above. The atoll, which has a small population (approximately 60 in 2014, but no indigenous inhabitants), is designated an "insular area" under the authority of the United States Department of the Interior.