United States Census
The United States Census is a decennial census mandated by the United States Constitution: Article I, Section 2, says, "Representatives and direct Taxes shall be apportioned among the several States ... according to their respective Numbers ... . The actual Enumeration shall be made within three Years after the first Meeting of the Congress of the United States, and within every subsequent Term of ten Years".  The United States Census Bureau (officially the Bureau of the Census, as defined in Title 13 U.S.C. § 11) is responsible for the United States Census.
The first census after the American Revolution was taken in 1790, under Secretary of State Thomas Jefferson; there have been 22 federal censuses since that time. The current national census was held in 2010 and the next census is scheduled for 2020 and much of it will be done using the internet. For years between the decennial censuses, the Census Bureau issues estimates made using surveys and statistical models, in particular, the American Community Survey.
Title 13 of the United States Code governs how the Census is conducted and how its data is handled. Information is confidential as per 13 U.S.C. § 9. Refusing or neglecting to answer the census is punishable by fines of $100, for a property or business agent to fail to provide correct names for the census is punishable by fines of $500, and for a business agent to provide false answers for the census is punishable by fines of $10,000, pursuant to 13 U.S.C. § 221-224.
The United States Census is a population census, which is distinct from the U.S. Census of Agriculture, which is no longer the responsibility of the Census Bureau. It is also distinct from local censuses conducted by some states or local jurisdictions.
Decennial U.S. Census figures are based on actual counts of persons dwelling in U.S. residential structures. They include citizens, non-citizen legal residents, non-citizen long-term visitors and illegal immigrants. The Census Bureau bases its decision about whom to count on the concept of usual residence. Usual residence, a principle established by the Census Act of 1790, is defined as the place a person lives and sleeps most of the time. The Census Bureau uses special procedures to ensure that those without conventional housing are counted; however, data from these operations are not considered as accurate as data obtained from traditional procedures.
The Census also uses hot deck imputation to assign data to housing units where occupation status is unknown. This practice has effects across many areas, but is seen by some as controversial because it may increase representation for reliably Democratic districts. However, the practice was ruled constitutional by the U.S. Supreme Court in Utah v. Evans.
The practice of including non-citizens in the official census figures is controversial because the census is used for the apportionment of seats in the House of Representatives, and, derived from that, of electors to the Electoral College. Groups like the Prison Policy Initiative assert that the census practice of counting prisoners as residents of prisons, not their pre-incarceration addresses, leads to misleading information about racial demographics and population numbers. Certain American citizens living overseas are specifically excluded from being counted in the census even though they may vote. Only Americans living abroad who are "Federal employees (military and civilian) and their dependents living overseas with them" are counted. "Private U.S. citizens living abroad who are not affiliated with the Federal government (either as employees or their dependents) will not be included in the overseas counts. These overseas counts are used solely for reapportioning seats in the U. S. House of Representatives." 
Censuses had been taken prior to the Constitution's ratification; in the early 17th century, a census was taken in Virginia, and people were counted in nearly all of the British colonies that became the United States.
Throughout the years, the country's needs and interests became more complex. This meant that statistics were needed to help people understand what was happening and have a basis for planning. The content of the decennial census changed accordingly. In 1810, the first inquiry on manufactures, quantity and value of products occurred; in 1840, inquiries on fisheries were added; and in 1850, the census included inquiries on social issues, such as taxation, churches, pauperism, and crime. The censuses also spread geographically, to new states and territories added to the Union, as well as to other areas under U.S. sovereignty or jurisdiction. There were so many more inquiries of all kinds in the census of 1880 that almost a full decade was needed to publish all the results. In response to this, the census was mechanized in 1890, with tabulating machines made by Herman Hollerith. This reduced the processing time to two and a half years.
For the first six censuses (1790–1840), enumerators recorded only the names of the heads of household and a general demographic accounting of the remaining members of the household. Beginning in 1850, all members of the household were named on the census. The first slave schedules were also completed in 1850, with the second (and last) in 1860. Censuses of the late 19th century also included agricultural and industrial schedules to gauge the productivity of the nation's economy. Mortality schedules (taken between 1850 and 1880) captured a snapshot of life spans and causes of death throughout the country.
The first nine censuses (1790–1870) were not managed by the Executive branch, but by the Judicial branch. The United States federal court districts assigned U.S. marshals, who hired assistant marshals to conduct the actual enumeration. The census enumerators were typically from the village or neighborhood and often knew the residents. Before enabling self-identification on the censuses, the US Census Bureau relied on local people to have some knowledge of residents. Racial classification was made by the census enumerator in these decades not by the individual.
|1||1790||August 2, 1790||3,929,326|
|2||1800||August 4, 1800||5,308,483|
|3||1810||August 6, 1810||7,239,881|
|4||1820||August 7, 1820||9,638,453|
|5||1830||June 1, 1830||12,866,020|
|6||1840||June 1, 1840||17,069,453||The census estimated the population of the United States at 17,100,000. The results were tabulated by 28 clerks in the Bureau of the Census.|
|7||1850||June 1, 1850||23,191,876||The 1850 census was a landmark year in American census-taking. It was the first year in which the census bureau attempted to record every member of every household, including women, children and slaves. Accordingly, the first slave schedules were produced in 1850. Prior to 1850, census records had only recorded the name of the head of the household and tabulated the other household members within given age groups.|
|8||1860||June 1, 1860||31,443,321||The results were tabulated by 184 clerks in the Bureau of the Census.
This was the first census where the American Indians officially were counted, but only those who had 'renounced tribal rules'. The figure for the nation was 40,000.
|9||1870||June 1, 1870||39,818,449|
|10||1880||June 1, 1880||50,189,209||This was the first census that permitted women to be enumerators.|
|11||1890||June 2, 1890
|62,947,714||Because it was believed that the frontier region of the United States no longer existed, the tracking of westward migration was not tabulated in the 1890 census. This trend prompted Frederick Jackson Turner to develop his milestone Frontier Thesis.
The 1890 census was the first to be compiled on a tabulating machine, developed by Herman Hollerith. The introduction of this technology reduced the time taken to tabulate the census from seven years for the 1880 census to two and a half years for the 1890 census. The total population of 62,622,250 was announced after only six weeks of processing. The public reaction to this tabulation was disbelief, as it was widely believed that the "right answer" was at least 75,000,000.
|12||1900||June 1, 1900||76,212,168|
|13||1910||April 15, 1910||92,228,496|
|14||1920||January 1, 1920||106,021,537||This was the first census that recorded a population exceeding 100 million.|
|15||1930||April 1, 1930
|16||1940||April 1, 1940||132,164,569||This is the most recent Census where individuals' data has now been released to the public (by the 72-year rule).|
|17||1950||April 1, 1950||150,697,361||Because of a 72-year rule, this census will be available for public inspection on April 1, 2022.|
|18||1960||April 1, 1960||179,323,175||Because of a 72-year rule, this census will be available for public inspection on April 1, 2032.|
|19||1970||April 1, 1970||203,302,031||This was the first census that recorded a population exceeding 200 million. Because of a 72-year rule, this census will be available for public inspection on April 1, 2042.|
|20||1980||April 1, 1980||226,545,805||Because of a 72-year rule, this census will be available for public inspection on April 1, 2052.|
|21||1990||April 1, 1990||248,709,873||Because of a 72-year rule, this census will be available for public inspection on April 1, 2062.|
|22||2000||April 1, 2000||281,421,906||Because of a 72-year rule, this census will be available for public inspection on April 1, 2072.|
|23||2010||April 1, 2010||308,745,538||For the first time since 1940, the 2010 Census is a short-form-only census, as the decennial long form has been replaced by the American Community Survey.
This was the first census that recorded a population exceeding 300 million. Because of a 72-year rule, this census will be available for public inspection on April 1, 2082.
- Taken one day late because June 1 was a Sunday.
- In the Alaska Territory, census-taking began on October 1, 1929.
The principal purpose of the census is to divide the house seats by population. In addition, collected data is used in aggregate for statistical purposes. Replies are obtained from individuals and establishments only to enable the compilation of such general statistics. The confidentiality of these replies is very important. By law, no one— neither the census takers nor any other Census Bureau employee— is permitted to reveal identifiable information about any person, household, or business. Without such protections, those living illegally in the United States or hiding from the government would be deterred from submitting census data.
By law (92 Stat. 915, Public Law 95-416, enacted on October 5, 1978), individual census records are sealed for 72 years prohibiting the release of personal information during individuals' lifetimes. The individual census data most recently released to the public is the 1940 census, released on April 2, 2012. Aggregate census data are released when available.
Historical FBI use of data
Under the administration of President Franklin D. Roosevelt the Federal Bureau of Investigation (FBI), using primarily census records, compiled (1939–1941) the Custodial Detention Index ("CDI") on citizens, enemy aliens, and foreign nationals, who might be dangerous. The Second War Powers Act of 1941 repealed the legal protection of confidential census data, which was not restored until 1947. This information facilitated the internment of Japanese-Americans, following the Japanese attack on the U.S. at Pearl Harbor on December 7, 1941 and the internment of Italian- and German-Americans following the United States' entry into World War II.
In 1980, four FBI agents went to the Census Bureau's Colorado Springs office with warrants to seize Census documents, but were forced to leave with nothing. Courts upheld that no agency, including the FBI, has access to Census data.
The census records and data specific to individual respondents are not available to the public until 72 years after a given census was taken, but aggregate statistical data derived from the census are released as soon as they are available. The 72-year rule is not law, but a rule posed by Roy V. Peel, Census Bureau Director, in a letter to Wayne C. Grover, Archivist, on August 26, 1952. Every census up to and including 1940 is currently available to the public and can be viewed on microfilm released by the National Archives and Records Administration, the official keeper of archived federal census records. Complete online census records can be accessed for no cost from National Archives facilities and many libraries, and a growing portion of the census is freely available from non-commercial online sources.
Census microdata for research purposes are available for censuses from 1850 forward through the Integrated Public Use Microdata Series (IPUMS), and scanned copies of each of the decennial census questionnaires are available online from many websites. Computerized aggregate data describing the characteristics of small geographic areas for the entire period from 1790 to 2010 are available from the National Historical Geographic Information System.
Regions and divisions
The bureau recognizes four census regions within the United States and further organizes them into nine divisions. These regions are groupings of states that subdivide the United States for the presentation of data. They should not be construed as necessarily being thus grouped owing to any geographical, historical, or cultural bonds.
|US Census Regions|
|Region 1: Northeast||Region 2: Midwest||Region 3: South||Region 4: West|
- Census-designated place (CDP), a populated community that lacks a separate municipal government
- Combined statistical area (CSA), an area that combines adjacent µSAs and MSAs
- List of U.S. states by historical population, state-level US Census data, 1790-2010, in table form
- Race and ethnicity in the United States Census
- United States metropolitan area (MSA), an area that includes adjacent communities to major cities
- United States micropolitan area (µSA), an urban area based around a core city or town with a population of 10,000 to 49,999
- Constitution of the United States
- "Decennial Census". American FactFinder. Retrieved 2008-02-24.
- "2020 Census will be done by Internet". Washington Post. Retrieved 1 April 2013.
- Smith, Annetta; Smith, Denise (2001). U.S Census Bureau Census Special Reports Series CENSR/01-2. US GPO.
- Meng, Xiao-Li (1994). "Multiple-Imputation Inferences with Uncongenial Sources of Input". Statistical Science 9 (4): 538–558. Unknown parameter
- "The Problem". Prisoners of the Census. September 26, 2005. Retrieved 2010-03-24.
- "Question and Answer Center". US Census Bureau.
- Martin Campbell-Kelly and William Aspray, "Computer a History of the Information Machine - Second Edition", Westview Press, pages 14-19 2004
- Porter, Robert; Gannett, Henry; Hunt, William (1895). "Progress of the Nation", in "Report on Population of the United States at the Eleventh Census: 1890, Part 1". Bureau of the Census. pp. xviii–xxxiv.
- Truesdell, Leon E. (1965). The Development of Punch Card Tabulation in the Bureau of the Census: 1890-1940. US GPO.
- "What is the purpose of the Census? What is the data used for?".
- "The "72-Year Rule"". U.S. Census Bureau.
- Minkel, JR (2007-03-30). "Confirmed: The U.S. Census Bureau Gave Up Names of Japanese-Americans in WW II". Scientific American. Retrieved 2009-11-02.
- El Nasser, Haya (2007-03-30). "Papers show Census role in WWII camps". USA Today. Retrieved 2009-11-02.
- Boyle, Mary (March 24, 2000). "Springs once tested Census' confidentiality". The Gazette (Colorado Springs).
- "History: The "72-Year Rule"". U.S. Census Bureau.
- National Archives and Records Administration. "How can I search the Census Records?". Retrieved December 13, 2008.
- "Discover your Ancestors".
- "The USGenWeb Free Census Project". Retrieved 2010-03-24.
- "The USGenWeb Census Project". Retrieved 2010-03-24.
- Anderson, Margo J. The American Census: A Social History. New Haven: Yale University Press, 1988. ISBN 0-300-04014-8
- Anderson, Margo J. Encyclopedia of the U.S. Census. Washington, DC: CQ Press, 2000. ISBN 1-56802-428-2.
- Dorman, Robert L. “The Creation and Destruction of the 1890 Federal Census,” American Archivist, 71 (Fall–Winter 2008), 350–83.
- Krüger, Stephen. "The Decennial Census", 19 Western State University Law Review 1, (Fall 1991); available at HeinOnline (subscription required)
- Lavin, Michael R. "Understanding the Census: A Guide for Marketers, Planners, Grant Writers, and Other Data Users". Kenmore, NY: Epoch Books, 1996. ISBN 0-89774-995-2.
- U.S. Department of Commerce, U.S. Census Bureau. Measuring America: the decennial censuses from 1790 to 2000. 2002
- U.S. Census Bureau official website
- National Historical Geographic Information System, a main source for freely downloading census data for the period 1790 through the present
- Integrated Public Use Microdata Series, the main source for census microdata for the period 1850 through the present
- CensusScope, from the Social Science Data Analysis Network (SSDAN)
- Historical U.S. Census Browser, from the University of Virginia Library
- Census Findings - Questions Asked in Each Census Year, from CensusFinder.com.
- How the Census Works, from HowStuffWorks, Inc.
- Sources of U.S. Census Data, from MIT Libraries
- 1890 Census Supplement Book-Set