The first United States census recorded a total population of 3,929,214 people in 1790.
The census was conducted under the authority of the Constitution, which required a population count for congressional representation and direct taxation. Federal marshals carried out the enumeration, beginning with an official census date of August 1, 1790.
The count covered the 13 states, plus the districts of Kentucky, Maine, and Vermont, as well as the Southwest Territory. It classified people into categories that included free white males, free white females, other free persons, and enslaved people. The categories reflected the laws and racial assumptions of the period.
The 1790 total is a historical baseline, not a modern-style demographic count. Some people may have been missed, and the enumeration did not include Native Americans living outside the tax system. Later censuses used changing classifications and expanded coverage, making direct comparisons more complex.