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U.S. Census: American Community Survey (ACS)


Use QuickFacts to easily locate a population and economic profile for nation, states, counties, and places.

Tables bring together data from multiple sources, including American Community Survey, Census of Population and Housing, County Business Patterns, Economic Census, Building Permits, and more.

Time Periods

ACS estimates are time periods not a point in time.

Do: express data in time periods

“The child poverty rate for the 2005-2007 period was X percent.”

Do: compare data using same types of estimates

Do: compare estimates using data from the same survey years (periods)

Do: compare data from non-overlapping periods

Example: 2005-2007 ACS 3-year estimate and the 2008-2010 ACS 3-year estimate


Don't: refer to data as a year (use the time period)

Don't: compare estimates from overlapping periods

Example: don't compare 2005-2007 ACS 3-year estimates and 2006-2008 ACS 3-year estimates

Margin of Error (MOE)

All ACS data are survey estimates. To help you interpret the reliability of the estimate, the Census Bureau publishes a margin of error (MOE) for every ACS estimate.


The American Community Survey (ACS) is a nationwide survey conducted on an ongoing basis to collect data about the nation, states, counties, and places. The data are released in single-year, 5-year, and 3-year time periods.

The ACS estimates replaces information formerly gathered in the decennial census; data on the "Short form"/sample.

Community Facts

Community Facts - Find popular facts (population, income, etc.) and frequently requested data about your community.

American FactFinder offers the option Community Facts. Search for the name of a state, county, city, town, or zip code.

Go to Community Facts webpage.

Select U.S. or a state from the box "Quick Links to Nation or State level Profiles" on the right side of the Guidance for Data Users page.
Four profiles are available:

  • Demographic
  • Social
  • Economic
  • Housing

Image of Community Facts menu for Newark, Delaware:

Data Release by Size of Place

Data from different sizes of geographies are released on different schedules. This insures statistical reliability for the smaller places.

Confidence Intervals

Subject Librarian

Rebecca Knight's picture
Rebecca Knight
Associate librarian
Reference and Instructional Services Department
Morris Library, Room 117H

Subjects: U.S. Government Information,
Delaware, census, family studies, RefWorks, APA style, and genealogy.

B.A., History. University of North Carolina, Chapel Hill. 1973.
M.S., Library Science. University of North Carolina, Chapel Hill. 1981.