Cowlitz County is a county located in the U.S. state of Washington. As of July 2007 its population was 100,467. The county seat is at Kelso
History
Its name derives from the anglicized version of the Cowlitz Indian term, Cow-e-liske, meaning either "river of shifting sands" or "capturing the medicine spirit." It was formed on April 21, 1854.