Censuses provide population numbers, household or family size and composition, and information on sex and age distribution. They often include other demographic, economic and health-related topics as well. The 1990 United States de jure census collected data by direct and self-enumeration. A short form questionnaire was mailed to all households and the long form questionnaire was completed by approximately one-sixth of housing units. Subjects covered by the census include housing, household demographics, employment, education, migration, and fertility. The census day was April 1, 1990.

A 5% differentially weighted sample of households that completed the long form questionnaire (12,501,046 individuals) is available through IPUMS International at the University of Minnesota. Dwellings are not identified in the microdata. The IPUMS sample for this census is notable because the variables have been harmonized with census data from other countries, allowing the data to be used together.