Unalaska is a volcanic island in the Fox Islands group of the Aleutian Islands in the US state of Alaska located at The island has a land area of 1,051 square miles (2,720 km2). It measures 79.4 mi (127.8 km) long and 34.7 mi (55.8 km) wide. The city of Unalaska, Alaska, covers part of the island and all of neighboring Amaknak Island where the Port of Dutch Harbor is located. The population of the island excluding Amaknak as of the 2000 census was 1,759 residents.
Unalaska is the second-largest island in the Fox Islands group and the Aleutian Islands. The coastline of Unalaska is markedly different in appearance than other major Aleutian Islands, with numerous inlets and peninsulas. The irregular coastline is broken by three long deep bays, Beaver Inlet, Unalaska Bay, and Makushin Bay, as well as by numerous smaller bays and coves. Unalaska's terrain is rugged and covered with mountains, and during the greater part of the year, the higher elevations are covered with snow. The highest point on Unalaska is the active volcano Mount Makushin.
Unalaska is the Aleut name for the island. Several theories about its origin exist; the most likely is that the name derives from the Russian word Ounalashka, an adaptation of the Aleut word for near the mainland, nawan Alaskax.