How many people did the first U.S. census count in 1790?

The first U.S. census counted 3,929,214 people in 1790.

The census measured the population as of August 2, 1790, following requirements in Article One of the Constitution and federal legislation. United States marshals visited households and recorded population categories under the rules established by Congress.

Virginia was the most populous state in the count, with 747,610 people, while Delaware was the least populous, with 59,094. The figures included free people and enslaved people, but the census classified them differently under the law of the time.

President George Washington and Secretary of State Thomas Jefferson both suspected that the total was an undercount. Travel was difficult, settlements were widely dispersed, and some people may have refused or failed to participate. The result was published in 1791 and became the baseline for later national censuses.