On what date was the first United States census conducted?

The first United States census was conducted on August 2, 1790.

The census was required by Article I, Section 2, of the Constitution, which called for a population count to apportion seats in the House of Representatives and determine direct taxation. Congress assigned the work to U.S. marshals, who were responsible for visiting households in the states and the Southwest Territory.

The initial enumeration reported 3,929,214 inhabitants. Later corrections produced a different total in some historical tables, so the date is a particularly useful fact for identifying the first census without confusing original and revised population figures.

The 1790 census asked for categories including free white males, free white females, other free persons, and enslaved people. Virginia was the most populous state, with 747,610 people in the published count. The results were published in 1791, and the census established the recurring federal enumeration that continues every ten years.