IPUMS Full Count Data (1790-1950)

IPUMS USA makes freely available to researchers worldwide full count U.S. Census microdata through 1950. This dataset includes over 800 million individual-level (1850-1940) and 7.5 million household-level records (1790-1840). The microdata represents the fruition of longstanding collaborations between IPUMS and the nation's two largest genealogical organizations —Ancestry.com and FamilySearch— to leverage genealogical data for scientific purposes. This microdata collection is possible due to the donations of an unprecedented scale of digitized census data by both Ancestry.com and FamilySearch.

Person-level microdata are available from 1850-1950. Full count data for 1790-1840 are available at the household-level. In contrast to the 1850-1950 U.S. censuses, the 1790-1840 historical censuses named only the head of the household and tallied household totals attached to that record.

IPUMS is continually improving the quality of these datasets by removing duplicate records, improving identification of household groups, applying numeric codes to the transcribed responses, etc. These improvements to the underlying data are periodically released via IPUMS USA. The variable VERSIONHIST identifies the public-release version of a dataset. Researchers can merge data between versions of the dataset using HISTID and identify updates, corrections, or improvements that may have been applied to the data. Users can review notes about major revisions for more information about specific data versions.

All data are coded and anonymous and can be downloaded via the IPUMS USA extract system. Restricted versions of these datasets are also available. A list of publications and grants that have used Full Count IPUMS data can be found on the Full Count Bibliography page.

Dataset Provenance

1900-1950 Full Count Data

The result of a collaboration with Ancestry.com.

1880 Full Count Data:

The result of a collaboration with the Church of Jesus Christ of Latter-Day Saints. These data are also available via IPUMS International.

1860-1870 Full Count Data:

The result of a collaboration with Ancestry.com.

1850 Full Count Data:

The result of a collaboration with the Church of Jesus Christ of Latter-Day Saints. These data are also available via IPUMS International.

1790-1840 Household-level Full Count Data:

The result of a collaboration and donations from both Ancestry.com and FamilySearch. For more information, see here.

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Restricted Versions

IPUMS also has a limited set of licenses to grant for access to the original restricted data with names and string variables. Users can also access the 1850 and 1880 datasets via IPUMS International.

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Revision History

Census Year Release Information
1950 Jan 2024 - Preliminary Release (Version 1)
1850-1880 Oct 2023 - 19th Century Update (Versions 2/3)

January 2024 - 1950 Full Count PRELIMINARY Release

This is the first IPUMS release of the 1950 full-count decennial census data. This data set contains microdata on over 152 million individuals in more than 46 million households. IPUMS continues to work with Ancestry to refine these data, identify and remove duplicate records, and fix transcription errors. Users should consider the status of this work while using these data, and be cognizant that this is a preliminary release only.

If you identify data issues not described below or have suggestions that would make the 1950 database more useful, we would welcome your feedback.

Users are cautioned to be aware of the following information:

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October 2023 - 19th Century Full Count Files

This release constitutes a major revision of the 19th century full-count decennial census files from 1850-1880. It includes updates and improvements to household definition, geography, nativity, occupational and demographic variables, new slave-related variables, and improvements to imputation and allocation processes. In general, efforts to increase standardization and improve harmonization have resulted in minor changes throughout the data, but users should take special note of some specific and more consequential updates, listed below:

Single-Year File Updates





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