The 1790 United States census recorded a population of 3,929,214.
The first census was conducted under the direction of Secretary of State Thomas Jefferson. Federal marshals visited households in the 13 states, plus the districts that later became Kentucky, Maine, Tennessee, and Vermont. The enumeration began in August 1790 and was completed in 1791, although some returns were delayed.
The count included free people and enslaved people, but it did not treat everyone equally in the representation formula. Under the Constitution’s original apportionment rule, three-fifths of the enslaved population was counted when determining representation and direct taxation. Native Americans living outside the tax system were excluded from the official count.
The 3,929,214 total includes 694,280 enslaved people and 3,172,006 free people counted in the census tables. The figure is sometimes confused with the free population alone. The census established the constitutional practice of counting the population every ten years.