Which U.S. census recorded a national population of 3,929,214 in 1790?

The First United States Census recorded a national population of 3,929,214 in 1790.

Conducted under Secretary of State Thomas Jefferson, the census began in August 1790. Marshals and their assistants visited households and recorded information required by federal law. The count covered the states and the districts then included in the Union, while some territories and Native American populations were not counted in the same way.

The census classified people into categories including free white males, free white females, other free persons, and enslaved people. It did not use modern questions about age, race, occupation, or household relationships. The total included 694,280 enslaved people, showing how deeply slavery was embedded in the early national population.

The Constitution requires a population count every ten years for apportioning representation in the House of Representatives. The 1790 census was therefore both a demographic record and an important administrative test for the new federal government. Its methods and categories changed substantially in later censuses.