Public Use Microdata Samples (PUMS) are computer-accessible files containing records for a sample of housing units, with information on the characteristics of each housing unit and the people in it.

The American Community Survey (ACS) PUMS files show untabulated population and housing unit records with individual response information.

What is PUMS Data?

PUMS data files contain records representing 1 in 1000, 1 percent, and 5 percent samples of the housing units in the United States and the persons in them.  Each PUMS file provides records for states and some of their geographic levels.

For example, they show how respondents answered questions on educational attainment, occupation, place of work, housing value, and so forth. 


The samples can be extended to analysis of the whole United States for many purposes, so comparative analysis across different groups is possible using the PUMS data. 


The webinar here explains the foundational aspects of working with the ACS PUMS files, including the organization of the files, the confidentiality of the files, accessing the data, geographic availability, and the PUMS documentation.


How do You Find PUMA Geographic Data?


A geographic data file is a resource to help grant applicants and service providers identify the Public Use Microdata Areas (PUMAs) that their project will serve.

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Note that the file is broken into two spreadsheets:

   (1) geographic data sorted by state and area name; and

   (2) geographic data sorted by PUMA - you may use the first spreadsheet to look up the PUMA based on their area name (i.e. county or city).

In sparsely populated areas, it may have been necessary to delineate PUMAs with non-contiguous parts to meet the minimum population criterion, when adjacent counties belonged to a metropolitan area or a local planning area.

US Census Bureau map are also helpful in providing graphics and information.


In some states, one or more PUMAs include noncontiguous parts. These PUMAs may occur for several reasons.

The Public Use Microdata Areas (PUMAs) for 1% and 5% are dissimilar geographical areas. 

On the 1% file, an effort was made to separate metropolitan areas from non-metropolitan areas. On the 5% file, an effort was made to keep meaningful socio-economic or planning areas together.

You may also be interested in Public Use Microdata Areas Program - Census Seeks Comments on Geographic Areas.