Steven Manson, Jonathan Schroeder, David Van Riper, and Steven Ruggles. National Historical Geographic Information System: Version 12.0 [dataset]. Minneapolis, MN: University of Minnesota, 2017. https://doi.org/10.18128/D050.V12.0
The National Historical Geographic Information System (NHGIS) provides free online access to summary statistics and GIS boundary files for U.S. censuses and other nationwide surveys from 1790 through the present. Boundary files include: counties and states since 1790, census tracts since 1910, metropolitan areas since 1950, places and county subdivisions since 1980, all standard census reporting areas since 1990, and SABINS school attendance areas for 2009-12. Summary tables from decennial censuses and the American Community Survey include county and state tables since 1790; census tract tables since 1910; and tables for all original census summary levels, down to census blocks, since 1970. Highlights of additional summary tables include County Business Patterns data (annual, 1970-2002), agricultural census data (1840-1950), religious bodies data (1850-1952), manufacturing census data (1840-1940), and 2010 census data for SABINS school attendance areas. NHGIS also includes time series tables that provide comparable statistics from multiple censuses linked together with standardized categories and codes for all years. NHGIS data are available through an online access system and are available free of charge to registered users at http://nhgis.org.
Past versions of data are available by request to registered IPUMS-NHGIS users. Please contact email@example.com. Archived versions of the data have been stored in fixed-format files with accompanying documentation and index files.
IPUMS-NHGIS data are continually revised. We archive annual snapshots and document changes between snapshots. The changes made to Version 12.0 before we archived Version 13.0 occurred between 8-9-2017 and 9-6-2018 as documented in the Release Log [https://www.nhgis.org/documentation/release-log].