The U.S. Census Bureau is commemorating America's 250th anniversary by highlighting key historical censuses that have tracked the nation's population, values, and societal changes since 1790. Mandated by the Constitution, the decennial census has been crucial for apportioning the U.S. House of Representatives for 236 of the country's 250-year history.
Early censuses faced unique challenges; the 1790 Census took 18 months to complete, with enumerators hand-recording data on any available paper. By 1830, uniform, printed schedule sheets were introduced, streamlining data collection and tabulation, and allowing for age data to be collected in 10-year ranges.
The 1920 Census marked a significant demographic shift, revealing a population exceeding 100 million and a major migration from rural to urban areas. Further modernization came with the 1960 Census, which was the first to primarily use self-enumeration and digital computers for processing nearly all collected data.