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US Census and American Community Survey

Information on the US Census, American Community Survey: History, data, mapping, and more.



This page has information about the United States decennial population census, also known as simply The Census. At the time of creating this resource, the 2020 census is underway.

The page has the following learning objectives:

  • Describe the history and mandate of The Census
  • Understand the methodology of data collection and what that means for scholarly research
  • Explore what information is available from historical and more recent censuses
  • Discover how to access the information needed for your research

The Census: History and Mandate

The Decennial Census

Every 10 years, the U.S. Census Bureau conducts a census to determine the number of people living in the United States. The U.S. Census Bureau conducts the census in years ending in zero, on Census Day, which is April 1. The Constitution of the United States, Article I, Sections 2 and 9, directs that a census or enumeration be taken: [source]

Representatives and direct Taxes shall be apportioned among the several States which may be included within this Union, 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, in such Manner as they shall by Law direct.

The data collected by the decennial census are used to determine the number of seats each state has in the U.S. House of Representatives. Apportionment is the process of dividing the seats in the House of Representatives among the 50 states based on the population figures collected during the decennial census. Redistricting is when state officials redraw the boundaries of the congressional and state legislative districts in their states after each census. [source]

The US Census Bureau

The Census Bureau's mission is to serve as the nation’s leading provider of quality data about its people and economy. The Census Bureau is an agency within the U.S. Department of Commerce, one of the executive departments of the federal government.

Thomas Jefferson directed the first census in 1790. As required by the U.S. Constitution, a census has been taken every 10 years thereafter. In 1840, the Census Act authorized the establishment of a centralized Census Office. In 1902, the Census Office became a permanent organization within the Department of Interior. A year later, it was renamed the Bureau of the Census and moved to the new Department of Commerce and Labor. [source]

The Census Bureau operates under the authorities of Title 13 and Title 26 of the U.S. Code. [source]


Conducting the Census

In the above video, UWM Professor Emerita Margo Anderson briefly describes the evolution of the United States Census.

Census Topics

Getting Census Data