Kelso, Washington

Kelso is a city in the southwestern part of the U.S. state of Washington and is the county seat of Cowlitz County. At the 2020 census, the population was 12,720. Kelso is part of the Longview, Washington Metropolitan statistical area, which has a population of 110,730. Kelso shares its long western border with Longview. It is near Mount St. Helens.