Information that the U.S. Census Bureau gathered in 1970 includes sex, race, age, marital status and the relationship between the household's head and each remaining member. Five percent of households were asked about Hispanic origin or descent.
Censuses from 1950 and 1960 undercounted residents because of distrust in the government. The U.S. Postal Service had carriers correct and update the Census Bureau's address register for densely populated areas to make sure that every household received a questionnaire.
Census day was on April 1, 1970, and postal carriers delivered the Census questionnaires a few days prior. The U.S. Census Bureau instructed urban residents to mail their responses back to the agency, and it instructed rural residents to wait for an enumerator to pick up the forms.