The 1790 United States census counted 3,929,214 people in the new nation.
The first federal census was conducted under the Census Act of 1790 and directed marshals to collect population information. The enumeration began on August 2, 1790, and covered the thirteen states, the districts of Kentucky and Maine, and the Southwest Territory. The final total included free people and enslaved people, but did not count most Native Americans under the census rules then in force.
The census was constitutionally important because population totals helped determine representation in the House of Representatives. It also provided the first nationwide demographic snapshot of the United States after independence and before the federal capital moved to Washington, D.C.
The published total was later revised upward to 3,929,214 after additional returns were found and tabulated. The census counted people by categories rather than using modern individual questionnaires, and its racial and legal classifications reflected the institutions of the late eighteenth century.