From Ancestry.com Wiki
This entry was originally written by Dwight A. Radford for Red Book: American State, County, and Town Sources.
Immigrants to the state of Washington came through the following ports: Aberdeen, Anacortes, Bellingham, Everett, Friday Harbor, Grey’s Harbor, Olympia, Port Angeles, Port Bernard, Port Wells, Princeton, Raymond, Seattle, South Bend, and Tacoma. Points of entry from Canada to Washington were Blaine, Curlew, Marcus, Oroville, and Sumas. These records are filed with the Seattle passenger and ship arrival lists and cover the period from 1890 to 1957. Customs passenger lists of vessels arriving at Port Townsend and Tacoma (1894–1904), passenger lists of vessels arriving at Seattle from Insular Possessions (1908–17), along with the Seattle passengers lists (1890–1957), lists of Chinese passengers arriving at Seattle and Port Townsend (1882–1916), alien certificates issued as “head tax” to immigrants at Vancouver and Victoria B.C. and surrendered at Seattle (1917–24), and crew lists of vessels arriving at Seattle (1903–17) are all at the National Archives—Pacific Alaska Region, as well as the The Family History Library (FHL).
There is a growing statewide index to naturalizations offered by the secretary of state.