Unalaska is a city in the Aleutians West Census Area of the Unorganized Borough of the U.S. state of Alaska. Unalaska is located on Unalaska Island and neighboring Amaknak Island in the Aleutian Islands off of mainland Alaska. The population was 4,376 at the 2010 census, which is 79% of the entire Aleutian West Borough. Almost all of the community's port facilities are on Amaknak Island, better known as Dutch Harbor or just "Dutch". It is the largest fisheries port in the U.S. by volume caught.