Census U.S. Decennial County Population Data, 1900-1990
The Census Bureau created an excellent resource for historic U.S. decennial population at the level of the state or county for each Census year from 1900-1990.
Spreadsheets and statistical software can read the comma-separated CSV file.
To download files in Internet Explorer, right click on them and select "Save Target As...".
Other sources of U.S. county population data:Single year U.S. county population data is available for 1969-on from Survey of Epidemiology and End Results (SEER)
The University of Virginia Library's Geostat Center is another source of pre-1969 county population data. They created electronic versions of the 1944-on County and City Data Books. These have county population estimates for 1930, 1940, 1943, 1950, 1960.Paper sources for pre-1969 data include Census Report P25-427 "Estimates of the population of counties and metropolitan areas, July 1, 1966",and
P25-461 "Components of population change by county: 1960 to 1970".
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