It is named for Bernard Fisher, a U.S. Geological Survey geologist who was killed in Umnak Pass.
Mount Westdahl, 5,426 feet (1,654 m) in elevation, is a stratovolcano of the Aleutian Range on the island situated at its western end.
When the Alaska National Interest Lands Conservation Act was passed on 2 December 1980, 910,000 acres (370,000 ha) of the island was designated as wilderness.
West of Unimak Island, the largest native mammal in the Aleutians is the red fox.
On April 1, 1946, during the 1946 Aleutian Islands earthquake, the lighthouse was struck by a tsunami.