The first United States Census is conducted.

The 1790 United States census was the first United States census. It recorded the population of the whole United States as of Census Day, August 2, 1790, as mandated by Article 1, Section 2, of the Constitution and applicable laws. In the first census, the population of the United States was enumerated to be 3,929,214 inhabitants.

The United States census is a decennial census that is legally mandated by the Constitution of the United States. The first census after the American Revolution was taken in 1790 under Secretary of State Thomas Jefferson. There have been 24 federal censuses since that time. The census includes territories of the United States. The United States Census Bureau is responsible for conducting the census.