Article 1, Section 2 of the U.S. Constitution mandates that the United States conduct a count of its population every 10 years to apportion the number of representatives each state will have in the U.S. House of Representatives. On March 1, 1790, President George Washington signed legislation into law—the “1790 Census Act"—assigning U.S. marshals the task of conducting the nation’s first census.
Since the first census in 1790, the U.S. Census Bureau has collected data using a census “schedule," also formally called a “questionnaire" or popularly called a “form". Between 1790 and 1820, U.S. Marshals conducting the census were responsible for supplying paper and writing-in headings related to the questions asked (i.e., name, age, sex, race, etc.). In 1830, Congress authorized the printing of uniform schedules for use throughout the United States.
The Census Act of 1880 replaced the U.S. marshals and their assistants—who conducted the censuses since 1790—with specially-hired and trained enumerators.
The 1940 Census included separate questionnaires to count the population and collect housing data. The 1960 and later censuses combined population and housing questions onto a single questionnaire mailed to households or completed during a census taker’s visit.
Between 1970 and 2000, the U.S. Census Bureau used two questionnaires. Most households received a short-form questionnaire asking a minimum number of questions. A sample of households received a long-form questionnaire that included additional questions about the household. In 2005, after years of testing and outreach to stakeholders and data users, the Bureau launched the annual American Community Survey (ACS) which includes the additional questions which used to be asked every ten years on the census long-form.
As a result of this ACS innovation, the 2010 Census was able to become a “short-form only" census with the 2010 Census questionnaire consisting of a single version with ten questions.
In 2020, the U.S. Census Bureau is again using a single short-form questionnaire, but with the public now having three ways to submit their responses to the 2020 census: online, by phone, or by mail.
Read more about the history of the decennial Census of Population and Housing on the U.S. Census Bureau website.