Census Browser Home | Examine Census Data Over Time | Codebook (PDF)

Where did the data and maps come from?

The original source of the each decade's data is the decennial census conducted by the U.S. Census Bureau. The source of the electronic data presented here was compiled by the Inter-university Consortium for Political and Social Research (ICPSR) under a grant from the National Science Foundation. The data selection was carried out under guidelines developed by the American Historical Association and reflect an interest in political and economic analyses.

The Historical United States County (HUSCO) boundary files used to produce the interactive maps were created by the Department of Geography & Anthropology at Louisiana State University.

What data are included?

The available data differ somewhat from decade to decade, according to what was collected in the census and the items chosen for transcription to electronic form. For the early decades, most of the enumerated items are included. For later decades, only a portion of characteristics have been transcribed. No information is available below the county level, and only states are included (no information on western territories before statehood, or for the District of Columbia).

In addition to basic counts of population and housing units, all decades contain information on race, gender, and some measure of household size and composition. Beginning with 1840, some economic characteristics such as education and occupation are included. Later decades have many variables, including ancestry, literacy, and income variables. In a few cases, the census data were augmented with information from the U.S. Department of Agriculture and the National Council of Churches of Christ.

Where can I find out more?

Information on the decennial census is available in Measuring America: The Decennial Censuses from 1790 to 2000. This PDF document is fairly large and may be difficult to download at slow modem speeds. Please email comments@census.gov if you have problems with this link.

Information on the evolution of county boundaries from 1900 to 1990 are available in the introduction to Population of Counties by Decennial Census: 1900 to 1990. The actual counts are available here.

For questions on methodology, see: Methodology of this site.

If you have questions concerning this resource, please contact us.

This site is made available with the cooperation and consent of the Inter-university Consortium for Political and Social Research (ICPSR).

Links to further historical census resources

Selected historical decennial census population and housing counts are available from the U.S. Census Bureau. Covering many different subjects areas and geographic levels, many key statistics can be located on this page.

The Census Bureau is adding digitized versions of historical census publications to its website for direct access by users. Working forward from 1790, the Census Bureau will eventually scan the population volumes from all decennial censuses, but not necessarily all volumes within each census. The files contain .pdf images of pages from census publications and are not searchable through adobe or web browsers. Users should refer to the finding guides available with each publication.

Measuring America contains basic methodological explanations for how census data was gathered over time. It includes the questionnaires and instructions to census marshalls, assistants, and enumerators for each census. This document includes notes on separate housing and employment censuses in the 20th century and historical notes for each census.

Statistical abstracts have been generated annually by the Census Bureau since 1878. They contain economic and social data with an emphasis on commerce. Data in these volumes also are reported on the national and state level, including organized territories. Tables of contents are included within each topic of these pdfs. As of May, 2004 the Census Bureau has completed digitization of abstracts from 1878-1900 and from 1950-current year.

The Census Bureau strongly suggests viewing the pdf files described above with Adobe Acrobat 6.

Information about individuals is NOT on this website

This website contains data compiled from the census, not records of individuals within the manuscript census records themselves. This website also contains no information about property ownership by individuals and does not contain lists of towns found within each county. For research on individuals, particularly for family history projects, consult the following webistes:



The data and terminology presented in the Historical Census Browser are drawn directly from historical volumes of the U.S. Census of Population and Housing.

Source Citation

Inter-university Consortium for Political and Social Research. HISTORICAL, DEMOGRAPHIC, ECONOMIC, AND SOCIAL DATA: THE UNITED STATES, 1790-1970 [Computer file]. Ann Arbor, MI: Inter-university Consortium for Political and Social Research [producer and distributor], 197?.


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