1790 United States census

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.

Congress assigned responsibility for the 1790 census to the marshals of United States judicial districts under an act, which with minor modifications and extensions, governed census taking through the 1840 census. "The law required that every household be visited, that completed census schedules be posted in 'two of the most public places within [each jurisdiction], there to remain for the inspection of all concerned...' and that 'the aggregate amount of each description of persons' for every district be transmitted to the president."

Contemporary perception
Both Secretary of State Thomas Jefferson and President George Washington expressed skepticism over the results, believing that the true population had been undercounted. If indeed an undercount was the result, possible explanations for it include dispersed population, poor transportation links, limitations of contemporary technology, and individual refusal to participate.

Loss and availability of data
Although the census was proved statistically factual, based on data collected, the records for several states (including Delaware, Georgia, New Jersey, and Virginia) were lost sometime between 1790 and 1830. Almost one-third of the original census data have been lost or destroyed since their original documentation. These include some 1790 data from Connecticut, Maine, Maryland, Massachusetts, New Hampshire, New York, North Carolina, Pennsylvania, Rhode Island, South Carolina, and Vermont; the validity and existence of most of these data, though, can be confirmed in many secondary sources pertaining to the first census.

No microdata from the 1790 population census are available, but aggregate data for small areas, together with compatible cartographic boundary files, can be downloaded from the National Historical Geographic Information System.

Data
Under the direction of the Secretary of State Thomas Jefferson, marshals collected data from all thirteen states (Connecticut, Delaware, Georgia, Maryland, Massachusetts including the District of Maine, New Hampshire, New Jersey, New York, North Carolina, Pennsylvania, Rhode Island, South Carolina, and Virginia), and from the Southwest Territory. The census was not conducted in Vermont until 1791, after that state's admission to the Union as the 14th state on March 4 of that year. (From 1777 until early 1791, and hence during all of 1790, Vermont was a de facto independent country whose government took the position that Vermont was not then a part of the United States.)

At 17.8 percent, the 1790 census's proportion of slaves to the free population was the highest ever recorded by any census of the United States.