Also provides mapping. Historic Census Data. Data prior to 1990 is primarily available in paper copy at federal depository libraries. See above for lists of libraries. There is no readily-available block group data prior to 1990.
Census tracts are often redefined or renumbered.
You need to look at the maps for each Census. Usually the printed tract volume will provide comparability with previous censuses. Household income was a new concept in 1980. Family income was commonly used through 1970. Until 1980, races in tables were listed as White, Negro, and other.