Unalaska (Nawan-Alaxsxa in Aleut) is an island in the Fox Islands group of the Aleutian Islands in the U.S. state of Alaska, at . The island has a land area of 2,720.918 km² (1,050.552 mi²), making it the 14th largest island in the United States and the 174th largest island in the world. 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.
It 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 innumerable inlets and peninsulas. However, its terrain is similar to most of the chain, rugged and covered with mountains.
The name Unalaska is Aleut. Several theories about its origin exist; most likely is that the name comes from a corruption of the Russian word Ounalashka from the Aleut word for near the mainland, nawan Alaskax. Unalaska is also the Aleut name for the island.
The island was discovered by Vitus Bering in 1741. A Russian settlement sprang up in 1759, but four years later it was destroyed by the Aleuts, together with four merchant ships. The massacre claimed the lives of 162 Russian settlers. The survivors managed to hold their own until 1764, when they were rescued by the Russians. This event triggered bloody reprisals against the natives which cost the lives of about 5,000 Aleuts.
President Ronald Reagan, in a May 31, 1988, speech in Moscow, mentioned the meeting of Americans and Russians on this island in the 19th century as an example of early U.S.-Russian friendship. On December 8, 2004, the Malaysian cargo ship Selendang Ayu ran aground off Unalaska Island, causing a large oil spill.