Kelso is a city in southwest Washington and the county seat of Cowlitz County. It sits on the Cowlitz River, about six miles from the Oregon state line, and shares its long western border with Longview, with which it forms a combined community often referred to as the Twin Cities. The 2020 census counted roughly 12,700 residents within the city, while the Longview metropolitan area is home to more than 100,000. The area's earliest known inhabitants were the Cowlitz people, who lived in longhouses in villages along the river. European-American settlement began in 1847, when Scottish surveyor Peter Crawford laid out the community that became Kelso. The city later grew on lumber manufacturing and rail, industries that shaped the wider Columbia River valley, and its gridded center extends across the Allen Street Bridge into Longview. Kelso's setting is framed by Mount St. Helens to the east, visible on clear days, and by the Cowlitz and Columbia rivers. The 1980 eruption of Mount St. Helens is part of the region's modern story, and parts of the city, including the Three Rivers Golf Course, were built on volcanic ash dredged from the Cowlitz River. The Cowlitz County Historical Museum preserves exhibits on the area's tribal, settler, and industrial past. Interstate 5, completed through the area in 1981, made Kelso a practical base for commuters, and the city functions today as a residential and government center with schools, retail, and services. Public education is provided by Kelso Public Schools, and Kelso High School competes in the Greater St. Helens League. Kelso suits residents seeking an affordable Pacific Northwest river-valley community with access to outdoor recreation and the Columbia River region to the south.