Chehalis (/ʃəˈheɪlɪs/ (ⓘ) shə-HAY-lis) is a city in Lewis County, Washington, United States. The population was 7,439 at the 2020 census. It is the county seat of Lewis County. The city is located in the Chehalis Valley and is bisected by Interstate 5 and State Route 6. It is adjacent to the city of Centralia and near communities like Napavine, Newaukum, and Adna.