The United States was the first country to call for a regularly held census. The Constitution required that a census of all "Persons...excluding Indians not taxed" be performed to determine the collection of taxes and the appropriation of seats in the House of Representatives. The first nine censuses from 1790 to 1870 were organized under the United States Federal Court system. Each district was assigned a U.S. marshal who hired other marshals to administer the census. Governors were responsible for enumeration in territories.

Census research is one of the first and most important steps in constructing a family tree. Everyone from genealogists to historians use the federal census for researching family histories. Deciphering census data, however, is not always easy.

   It is usually best to begin a census search in the most recently available census records (1930) and to work from what is already known about a family. With any luck, birthplaces and other clues found in these more recent records will point to locations of earlier residence