The name "Chehalis" derives from '''', the name of principal village of the Lower Chehalis people and what is today
Westport, Washington. The name, which means "sand", originally only replied to that village and its inhabitants. After colonization, it became the name of the Chehalis River and a collective term to refer to both the Upper and Lower Chehalis peoples living along it as a whole. The traditional territory of the Lower and Upper Chehalis peoples included the Chehalis River and its tributaries, including the
Black,
Cowlitz,
Elk,
Johns,
Newaukum,
Satsop,
Skookumchuck, and
Wynoochee rivers. The Upper and Lower Chehalis people were never party to any ratified treaty. In 1864, a reservation was formally established by
executive order for the Upper and Lower Chehalis peoples in 1864. On October 1, 1866, another executive order opened up to homesteading by non-Native settlers. of the total reservation lands were retained for schooling. Another section of the reservation was taken into public domain by the federal government on November 11, 1909. The Confederated Tribes of the Chehalis Reservation was formally established through the creation of its constitution and bylaws on July 15, 1939. In 1906, the population of the tribe was 149. In 1984, the population had grown to 382. ==Government==