United States Census

The United States Census is mandated by the United States Constitution. The population is enumerated every 10 years and the results are used to allocate Congressional seats ("congressional apportionment"), electoral votes, and government program funding. (Some states also conduct statewide censuses as the need arises; these are called state censuses.)

The census is performed by the United States Census Bureau. The first census after the American Revolution was taken in 1790; there have been 21 federal censuses since that time. The next census will be taken in 2010. A detailed page on the most recent census can be found at United States Census 2000.

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. In recent censuses, estimates of uncounted housed, homeless, and migratory persons have been added to the directly reported figures.

For years between the decennial censuses, the Census Bureau issues estimates made using surveys and statistical models.

The practice of including non-citizens in the official census figures is highly controversial as the census is used for the apportionment between the states of seats in the House of Representatives, and derived from that, of electors to the Electoral College. The Census also employs the practice of using hot deck imputation to assign data to housing units where occupation status is unknown. This practice has effects across many types of 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.

Census data and questionnaires
The census records and data specific to individual respondents is not available to the public until 72 years after they were taken but detailed statistical data derived from the census is freely available contemporaneously. Every census up to 1930 is currently available to the public and can be viewed on microfilm released by the National Archives and Records Administration, the official keeper of old federal census records. These census records are also available online from various sources such as Ancestry.com and FamilySearch.com, which have all released census records available for a subscription. The 1940 census will be available for public review in 2012.

Data is available for all surviving census records, including recent records up to the 2000 census, for research purposes from IPUMS USA. Further, scanned copies of each of the decennial census questionnaires distributed in the United States from 1960 forward are available on-line from IPUMS International.

The contemporaneous statistical data is available in various formats from the Bureau with one of the more popular formats being as layers formatted for the public-domain GIS tool, LandView.

History of the U.S. Census
Censuses had been taken prior to the Constitution's ratification; in the early 1600s, a census was taken in Virginia, and people were counted in nearly all of the British colonies that became the United States.

Down through the years, the country's needs and interests became more complex. This meant that there had to be statistics 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; in 1840 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 censuses of 1880 and 1890 that almost a full decade was needed to publish all the results.

For the first six censuses (1790-1840) enumerators recorded only the names of the heads of household and did a general demographic accounting of the remaining members of the household. Beginning in 1850, all members of the household were named by the enumerator. The first slave schedules were done 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 U.S. Executive Branch, but by the U.S. Judicial Branch. The United States Federal Court districts assigned U.S. marshals, who hired assistant marshals to do the actual census-taking.

First Census of the United States (1790)
The first Census was taken August 2, 1790. The federal census records for the first census are missing for five states: Delaware, Georgia, Kentucky, New Jersey and Virginia. They were destroyed some time between the time of the census-taking and 1830. The census estimated the population of the United States at 3,929,214.

Second Census of the United States (1800)
The second Census was taken August 4, 1800.

Third Census of the United States (1810)
The third Census was taken August 6, 1810.

Fourth Census of the United States (1820)
The fourth Census was taken August 7, 1820.

Fifth Census of the United States (1830)
The fifth Census was taken June 1, 1830.

Sixth Census of the United States (1840)
The sixth Census was taken June 1, 1840. 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.

Seventh Census of the United States (1850)
The seventh Census was taken June 1, 1850. The 1850 census was a landmark year in American census-taking. It was the first year in which the census bureau attempted to count 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 broad statistical accounting of other household members, (three children under age five, one woman between the age of 35 and 40, etc.).

Eighth Census of the United States (1860)
The eighth Census estimated the population of the United States at 31,400,000. 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 'nenounced tribal rules'. The figure for the nation was 40,000.

Eleventh Census of the United States (1890)
The eleventh Census was taken June 1, 1890. The 1890 census announced that the frontier region of the United States no longer existed and therefore the tracking of westward migration would no longer be tabulated in the 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. This introduction of 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. Ironically, the public reaction to this tabulation was disbelief, as it was widely believed that the "right answer" was at least 75,000,000.

The logistical difficulties in compiling the census drove computing technology for the next fifty years until computers became widespread in industry. IBM's first electronic computer was created primarily to deal with the needs of the census in addition to military and academic uses.

This census is also notable for the fact it is the only one for which the original data is no longer available. Almost all the population schedules were destroyed in a fire in 1921.

Fifteenth Census of the United States (1930)
The fifteenth Census was taken on April 2, 1930, except in Alaska Territory, where census-taking began October 1, 1929.

Sixteenth Census of the United States (1940)
The sixteenth Census was taken on April 1, 1940. Because of a 72-year privacy law, this census will not be available for public inspection until April 1, 2012.

Twenty-second Census of the United States (2000)
The 22nd Census of the United States took place on April 1, 2000. Because of a 72-year privacy law, this census will not be available for public inspection until April 1, 2072.

Respondent confidentiality
The sole purpose of the censuses and surveys is to secure general statistical information. 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 &mdash; neither the census takers nor any other Census Bureau employee &mdash; is permitted to reveal identifiable information about any person, household, or business.

Without such protections, certain people living illegally in the United States or in any other way hiding from the government would be deterred from submitting census data.

Historical FBI abuses of census data
As with any large collection of personal data which can be traced back to individual persons, the potential for abuse of census data exists. During the period of 1939–1941, the FBI, using primarily census records, compiled the Custodial Detention index ("CDI") on citizens, "enemy" aliens and foreign nationals who might be dangerous, which later led to large-scale internment of Japanese-Americans.

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.

Quantitative state rankings
In the last decade, the Census Bureau has begun to rank the states of the Union in qualitative terms based on their quantitative figures so that people can more easily understand the changing dynamics of the country. The goal of this effort is to stir up national pride and understanding along with governmental participation at the state and federal level.

General references

 * Anderson, Margo J. "Encyclopedia of the U.S. Census". Washington, DC: CQ Press, 2000. ISBN 1-56802-428-2.
 * Campbell-Kelly, Martin, and Aspray, William. Computer: A History of the Information Machine. New York: Basic Books, 1996.  ISBN 0-465-02990-6.


 * Lavin, Michael R. "Understanding the Census: A Guide for Marketers, Planners, Grant Writers, and Other Data Users". Kenmore, N.Y. : Epoch Books, 1996. ISBN 0-89774-995-2.