Unalaska (Aleut: Iluulux) 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. 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. It includes Dutch Harbor Naval Operating Base and Fort Mears, U.S. Army, a U.S. National Historic Landmark.