Washington Census
Indexes in book and microfiche format are available for the 1860, 1870, and 1880 censuses. A soundex (phonetic) index is available on microfilm for part of the 1880 and all of the 1900, 1920 and 1930 censuses. For 1910 the Family History Library has a street index for Seattle (FHL fiche 6331481).
Mortality schedules exist for the 1850 (as part of Oregon Territory), 1860, 1870, and 1880 censuses. The mortality schedules for 1860 to 1880 are available at the DAR library in Washington D.C. and at the Washington State Library. The Family History Library has copies of the 1860, 1870, and 1880 mortality schedules.
Territorial and State
In addition to the federal censuses, territorial and state censuses also exist for a few counties for various years 1857-1892. These generally include heads of households only. These partial censuses are available at the Washington State Library and the Family History Library (beginning with FHL film 1841781).