The first United States census was conducted in 1790.
Census Day was August 2, 1790, and the enumeration recorded 3,929,214 inhabitants in the United States. The Constitution required a population count for congressional apportionment, and Congress passed legislation establishing the process during the first federal administration.
U.S. marshals, rather than a permanent census bureau, carried out the count. The law required household visits and instructed officials to post completed schedules publicly in two places within each district. The categories reflected the era's legal and social system and included free people and enslaved people separately.
Virginia was the most populous state in the original count. Historical sources may show slightly different totals because later corrections revised the figures first published in 1790. The census has been conducted every ten years since then.