https://en.wikipedia.org/wiki/1790_United_States_census
The United States census of 1790 was the first census of the whole United States.It recorded the population of the United States as of Census Day, August 2, 1790, as mandated by Article I, Section 2 of the United States Constitution and applicable laws. In the first census, the population of the United States was enumerated to be 3,929,214.