Much of the Northwest Ethnohistory Collection consists of duplicates of primary and secondary materials available in other repositories and is not archival in composition. These records include articles, research notes, legal cases, and other information collected in the last half of the twentieth century. The value of the collection lies in the research convenience of having these unique and difficult to find materials located in one source. The collection has not been processed and the collection inventory provides only file level inventory of the collection. The records were initially "reorganized" into classification system based on Native American tribal associations by a staff member in the Anthropology Department. That system was abandoned about halfway through the collection and final files represent the filing system used by the creators.

The collection includes information relating to various Native American tribes in the Pacific Northwest, especially Washington State, including the Chehalis, Shoalwater, Chinook, Clallam, Clatsop, Cowlitz, Duwamish, Haida, Klamath, Klickitat, Kwakiutl, Lummi, Makah, Muckleshoot, Nisqually, Nooksack, Puyallup, Quileute, Quinault, Salish, Semiahmoo, Skagit, Snohomish, Squaxin, Steilacoom, Suiattle-Sauk, Swinomish, and Suquamish tribes.