2010 Census Redistricting Data Summary Files (P.L. 94-171)
Block-level population and housing counts from the 2010 Census, used to keep tract figures comparable across the 2020 boundary change.
"Public Law (P.L.) 94-171, enacted by Congress in December 1975, requires the Census Bureau to provide states the opportunity to identify the small area geography for which they need data in order to conduct legislative redistricting." The resulting summary file is the first product of each decennial census and reports population and housing occupancy counts down to the census block, the smallest unit the Bureau tabulates.
Coverage#
We use the 2010 release for the 50 states and the District of Columbia. The counts reconcile to the published 2010 totals of 308,745,538 residents and 131,704,730 housing units for the United States.
The Island Areas — American Samoa, Guam, the Northern Mariana Islands and the U.S. Virgin Islands — were enumerated under a separate 2010 program and have no file in this series. As a result, 132 tracts of 2010 vintage have no block-level 2010 count available. This is a property of the published data, not of our loading.
How we use it#
Census tract boundaries were redrawn for 2020, so a tract number does not always describe the same ground before and after. These block counts describe how people and housing were distributed in 2010, which is what allows figures reported on 2010 tracts to be placed on 2020 tracts and compared over time. They are reference geography and produce no metric of their own.
Considerations#
Counts are as of April 1, 2010 and are never revised. Where 2010 and 2020 tracts do not correspond, any comparison across the change is an approximation rather than a like-for-like reading, and it is weakest where boundaries were split or merged most heavily.
Citation#
U.S. Census Bureau, 2010 Census Redistricting Data (P.L. 94-171) Summary File.
Per Census Bureau guidance, the Bureau is cited as the source of the original data only.
References#
- 1US Census Bureauhttps://www.census.gov/data/datasets/2010/dec/redistricting-file-pl-94-171.html
- 2Census Bureau guidancehttps://www.census.gov/about/policies/citation.html