The Decennial Census is mandated by the U.S. Constitution.
The Decennial Census was originally set up to apportion the House of Representatives seats in Congress.
The Decennial Census has been expanded over time to cover other aspects of the American economy.
The current Decennial Census is actually two censuses: 1) the Census of Population and 2) the Census of Housing. Jointly called the Census of Population and Housing.
The Census of Population and the Census of Housing are taken concurrently every ten years.
Between 1940 and 2000, there were two versions of the census questionnaire. The short form was asked of every household and covered basic population characteristics. The long form was asked of about one in six households and covered additional questions on socioeconomic and housing issues.
In 2010 the American Community Survey replaced the census long form.
Individual responses to the Decennial Census are confidential for 72 years.
Preliminary Data is released within a year of the Census being conducted. National and state level summary data are released first. Detailed data and data for smaller geographic areas are released over time. When searching for census data keep the following in mind:
Census data is available for many levels of geography, including states, counties, cities and towns, ZIP Code Tabulation Areas, census tracts, blocks, and much more. Not all data is available for all geographic levels. In general, the larger the geographic area, the more likely data will be available.
Increasingly the Census Bureau has been making demographic data available online. As new data becomes available, older statistics drop out of the database. Besides materials provided by the Census Bureau, third party vendors also offer census related products. Other census related materials are held by OSU Libraries and are searchable via the catalog and/or online.
The Ohio State University Libraries (OSUL) maintains a collection of United States Census materials produced by the U.S. Census Bureau, commercial publishers, and state agencies. This collection includes:
Paper Census volumes, 1790-present.
A non-circulating collection of decennial census publications is housed in the Thompson Library. Duplicate copies of some volumes may be requested from the Book Depository.
CD-ROMs and DVDs.
The library holds CD-ROMs and DVDs produced by the U.S. Census Bureau, Ohio Department of Development Office of Strategic Research, and other government entities. These products may be borrowed for use on lab or personal computers. Search the library catalog for call numbers and locations.
Databases such as Geolytics. Commercially produced databases based on the U.S. Census. (Please make an appointment to use Geolytics with the Microforms and Government Information or Map Room staff).
Most census materials held are shelved by LC rather than SuDoc number. OSUL also provides access to census data available via the Internet and Reference Librarians and Staff are available to provide further assistance.
The OSU Libraries do not collect Census schedules. They are available at the following Ohio libraries. (Holdings and hours vary. Contact the libraries for more information.)
Columbus Metropolitan Library. Main Library. Local History & Genealogy Services.
Ohio History Connection Archives/Library. (formerly the Ohio Historical Society Archives/Library)
The Public Library of Cincinnati and Hamilton County. Main Library. Genealogy and Local History Department.
Indexes to the schedules are available. Some of which are listed below.
Catalog of NARA Microfilm
The 1790-1890 Federal Population Censuses: Catalog of National Archive Microfilm. (OSU Book Depository)
1900 Federal Population Census: a Catalog of Microfilm Copies of the Schedules. (OSU Book Depository)
The 1910 Federal Population Census: a Catalog of Microfilm Copies of the Schedules. (OSU Book Depository)
The 1920 Federal Population Census: a Catalog of National Archives Microfilm. (OSU Book Depository)
The 1930 Federal Population Census: Catalog of National Archives Microfilm. (Not held by OSUL.)
Census: Get Started. (Boston College. University Libraries)
Census Research Guide: Home. (University of California – San Diego. The Library)
Census Resources. (Northern Michigan University. Lydia M. Olson Library) Although Michigan-centric, has useful listing of hard copy, electronic and microfiche resources for conducting census research.
Research Guide - U.S. Census and Demographic Information: Census Introduction. (University of Michigan. University of Michigan Library)
Research Guides - Decennial Census (Population & Housing). (Columbia University Libraries. Information Services)
Research Guides - United States Decennial Censuses General Research Guide. (Mississippi State University. University Libraries)
U.S. Census Data. (New York University. NYU Libraries)
U.S. Census: Home - Census Geography. (University of Delaware. Library) Focus on census geography.
United States Census Statistics and Information. (University of California – Los Angeles. UCLA Library) Links to early census publications arranged by decades.