Kelso is located in Cowlitz County. About 12,720 people live here (as of 2020). Between 2010 and 2020, the population grew from 11,925 to 12,720. The region is at 23 meters above sea level. The area covers about 21.7 square kilometers. There are about 718 streets in Kelso. The region was founded in 1884. The postal codes are 98626. The dialing code is 360. Kelso is city and county seat in southwestern Cowlitz County, Washington, United States. Among other things, Kelso has public Transport, restaurants, cafés, schools, hairdressers and pharmacies. More information at
www.kelso.gov.