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University Library, University of Illinois at Urbana-Champaign

Microdata Use: U.S. Census Microdata

Major sources of microdata by country and subject and tips research use

U.S. Census Microdata

If you are interested in finding, using, or browsing U. S. Census microdata, then the data sources in this category are right for you. The U. S. Census microdata files are often referred to as PUMS and IPUMS (Integrated Public Use Microdata Series), consisting of 1% samples of the long-form questionnaire, stripped of any personal identifiers and grouped in special geographic units of at least 100,000 people to protect confidentiality. These census microdata can be used as raw data for users to create their own customized tables that are unavailable through published census resources such as American FactFinder and

Data Source Description
US Census Bureau: PUMS Files Brief description and order information for a list of microdata (PUMS) files (on disks or CDs or tapes) produced and released by the U. S. Census Bureau, including the microdata files from American Community Survey (ACS) and  Decennial Census.  The ACS files are from selected samples of the surveys conducted during 1996-1998, and the Decennial Census PUMS files are from the 1990, 1980, 1970, 1960, 1950, and 1940 Census. American Community Survey files are available for downloading and on CD-ROM, and also available through American FactFinder. All these files are archived by and available at ICPSR as well.
ICPSR Browse one of the largest institutional data repositories for U.S. Census public use raw data files. Data files all come with associated metadata and can usually be downloaded in a variety of formats. 
IPUMS-USA, Minnesota Population Center, University of Minnesota The IPUMS produced by the Minnesota Population Center at the University of Minnesota, is a series of historical census microdata that has high precision samples and comprehensive documentation. IPUMS-USA  is a coherent census database for the U. S. Censuses spanning 1850 to 1990. It is available for free access and use. Once users register, they can use the IPUMS Data Exaction System to acquire census microdata according to their own specifications with sample size, year of census, variables, etc.
1940 - 1990 Census PUMS Files, available at the Consortium for International Earth Science Information Network (CIESIN) CIESIN, located at Columbia University in New York, is a private, government-sponsored research organization that is dedicated to disseminating information on global environmental change and demographics. It archived some of the U. S. Census PUMS files and made them available (in ASCII format and compressed) to users for free. The PUMS datafiles include sample data from 1940 (1 percent, national file), 1950 (1 percent, national file), 1960 (1 in 1000, national file), 1970 (1 in 1000, national files), 1980 (1 percent and 5 percent files by state), and 1990 (1 percent and 5 percent files by state), and an added file contains the 15% sample for the year 1970.
2000 US Census Release Schedule for PUMS Files This summary table of Census products from the year 2000 presents different data files and organizes them by date of release, file type, and the smallest geographic unit.