The first United States census recorded a population of 3,929,214 in 1790.
The census counted residents of the new United States as of August 2, 1790. Congress authorized it under the Constitution, which required an enumeration for representation and direct taxation. United States marshals conducted the count rather than a permanent census agency.
Virginia was the most populous state in the reported totals, while Delaware was the least populous. The count covered the states and the Southwest Territory, but it did not include all land that later became part of the United States.
The 1790 census used categories and rules that reflected the era’s legal and social system, including separate counts for enslaved people and free people. Modern population comparisons should therefore be made carefully, because the census did not measure population in the same way as later censuses.