Adak, formerly Adak Station, is a city located on Adak Island, in the Aleutians West Census Area, Alaska, United States. At the 2020 census, the population was 171, down from 326 in 2010. It is the westernmost municipality in the United States and the southernmost city in Alaska. The city is the former location of the Naval Air Facility Adak, NAVFAC Adak.