The National Historical Geographic Information System (NHGIS) Data Finder provides easy access to summary tables and time series of population, housing, agriculture, and economic data, along with GIS-compatible boundary files, for years from 1790 through the present and for all levels of U.S. census geography, including states, counties, tracts, and blocks.
Published by IPUMS, a federally funded project of the University of Minnesota. IPUMS provides downloadable data and microdata sets from the U.S. and international sources, harmonizing variables so data is comparable and consistent. IPUMS platforms includes data from numerous U.S. government entities, such as the NIH, NSF, FDA, Census, BLS, CDC, NASA. Free access after creating an account. See the user guide and tutorials.