Ketchikan is a city in and the borough seat of the Ketchikan Gateway Borough on Revillagigedo Island of Alaska. It is the state's southeasternmost major settlement. Downtown Ketchikan is a National Historic Landmark District. With a population at the 2020 census of 8,192, up from 8,050 in 2010, it is the sixth-most populous city in the state, and thirteenth-most populous community when census-designated places are included.