The first U.S. census recorded a total population of 3,929,214 people in 1790.
The census counted the population as of August 2, 1790, under authority granted by Article One of the Constitution. Congress assigned the work to U.S. marshals, who visited households and compiled returns for the new federal government. The results were published in 1791 in a 56-page report.
The figure included free people and enslaved people under the categories used by the census law. It did not represent a modern-style demographic count, and both George Washington and Secretary of State Thomas Jefferson suspected that the total was an undercount. Differences in transportation, settlement patterns, record-keeping, and participation affected the results. Virginia was the most populous state in the census, while Delaware was the least populous among the states.