"Federal decennial population census schedules contain a wealth of information for genealogists as well as for historians and social scientists. They are of use to the family historian and researcher interested in westward expansion, the status of free and slave labor, regional and local history, immigration, and so forth. Often they contain evidence for proving citizenship.
As a rule the information gathered in each successive census is progressively more detailed. The schedules for the period 1790-1840 show the names of enumerated heads of families only, other members of the family being simply tallied by age groups, sex, and race (white or Negro). All subsequent enumerations, however, list each individual in a household by name with exception of the slave schedules for 1850 and 1860, which show only the name of the owner and the number of his slaves by age group and sex. The 1850 census was the first to record each person's age, occupation if over age 15, and place of birth. If the parent of a person enumerated in the 1870 schedules was of foreign birth, that fact is indicated. The 1880 census adds the relationship of each individual to the head of the family."
"Most of the 1890 population schedules were destroyed or badly damaged by fire; the few surviving segments have been microfilmed. The 1890 special census of Union veterans and widows of Union veterans of the Civil War gives information about the military service of each veteran named and the post office address of each listed person who was living at the time of the enumeration." Introduction to Federal Population Censuses, 1790-1890; a catalog of microfilm copies of the schedules. NARA, Washington: 1971. (located at the Terrell Library Reference Desk and in the Microforms Room)
The 1940 census records were released by the US National Archives April 2, 2012, and brought online through a partnership with Archives.com. This 1940 census website allows you full access to the 1940 census images, in addition to 1940 census maps and descriptions.
"On April 2, 2012, the National Archives and Records Administration will make individual records from the 1940 Census available to the public for the first time. The 1940 Census was conducted during a momentous time in our nation’s history, as the Great Depression was winding down and not long before our entry into World War II (although the war was already raging in Europe). It marked the only census conducted during the lengthy presidency of Franklin D. Roosevelt. It was also notable for many other reasons, as detailed below. In this edition of Profile America Facts for Features, we compare notable 1940 Census facts with corresponding information from the 2010 Census. Included is an early look at plans for the 2020 Census."
U.S. Census Bureau
Note: National Archives resources for earlier censuses can be found at NARA's Census Records page.
Population Schedules are detailed records of the federal government's decennial census of American households. Because they include names and personal information they are not released until 72 years after the census is taken. The microfilm is located in the Microforms Room of Holland Library (first floor west). The reels are copies of the schedules held by the National Archives and Records Administration (NARA),
1790-1890 (1st-11th censuses, all states): cabinets 20-29, south wall of the Microforms Room in Holland Library. Note that the 1890 census was largely destroyed by fire in 1921 in Washington, D.C. and only small portions of it remain. 1890 includes Special Schedules of the Eleventh Census (1890) Enumerating Union Veterans and Widows of Union Veterans of the Civil War.
1900-1930 (12th-15th censuses, Idaho, Oregon, Washington only) cabinet 127:
1900 Idaho HA331.5 1900 reels no. 1-4; Oregon HA591.5 1900 9 reels; Washington HA691.5 1900 reels no. 1-14
1910 Idaho HA331.5 1910 (8 reels); Oregon HA591.5 1910 (reels no. 1278-1291); Washington HA691.5 1910 (23 reels)
1920 Idaho HA331.5 1920 (9 reels); Oregon HA591.5 1920 (15 reels); Washington HA691.5 1920 (27 reels)
1930 Idaho HA331.5 1930 10 reels, Reels T395-404; Oregon HA591.5 1930 20 reels, Reels 1939-1958 ; Washington HA691.5 1930 42 reels, Reels T2484-T2525
1885-1940 Indian Census Rolls: E98.C3 U56 cabinet 116 in the Microforms Room
There are census worksheets on top of the 1790-1890 cabinets (west wall of Microforms Rm).
Microfilmed indexes are available for the 1880-1930 censuses using the Soundex indexing system. While WSU Libraries does not have the Soundex indexes, Spokane Public Library's Genealogy Research service and NARA's Pacific Alaska Region Genealogy Research resources are two places in Washington State that do. The Soundex Indexing System site explains the coding rules.
Indexes to the 1790-1870 censuses have been published by various companies and can be found at larger libraries.