The United States Census Bureau is a sub agency of the Commerce Department.The census is conducted every 10 years as mandated by the U.S. Constitution in order to draw Congressional District lines. The census determines whether states maintain, increase or decrease th number of congressional seats based on these census counts. Since the first Census in 1790, the information collected and how it is used has changed dramatically. Although the original purpose of the census was to designate the size and shape of congressional districts, the census now provides valuable data which enables all levels of government to determine how tax dollars are spent. Businesses, non-profit organizations, journalists, students and researchers also are able to access and use the collected data.
In addition to the decennial census of the United States, the bureau conducts several other surveys which provides detailed demographic information between each census. One of the most detailed of these surveys is the American Community Survey (ACS) which is conducted annually except during the decennial census year. The 2009 ACS asked 48 questions which was sent to randomly selected households throughout the U.S. It provides information about income, education, household type and makeup, race and ancestry. Other surveys include economic surveys and government surveys. For more information about the Census can be found at the United States Census Bureau website.
[Source: U.S. Census Bureau]
According to the "72-Year Rule," the National Archives releases census records to the general public 72 years after Census Day. As a result, the 1930 census records were released April 1, 2002, and the 1940 records were released April 2, 2012. The 1950 census records will be released in April 2022. For those who need prove of citizenship, individuals are able to request their census records for a fee at http://www.census.gov/topics/population/genealogy/agesearch.html