Geographic Areas and Concepts for the American

Community Survey

Updated February 2013

Overview

• Basic Census Bureau geography

• Geographic areas for which ACS data are available

• Geographic area concept and definition issues to be aware of when using ACS data

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Types of Geographic Areas

• Legal/administrative areas– have legally described boundaries; they may

provide governmental services or may be used to administer programs

• Statistical areas– defined primarily for data tabulation and

presentation purposes

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Census Geographic ConceptsLegal/Administrative and Statistical Areas

Legal/Administrative Areas Statistical Areas

Nation Regions

States Divisions

Counties Census County Divisions

Minor Civil Divisions Census Designated Places

Incorporated PlacesMetropolitan and Micropolitan Statistical Areas

Congressional Districts Urban / Rural Areas

School Districts Census Tracts

Voting Districts Block Groups

ZIP Code Tabulation Areas Public Use Microdata Areas

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ACS Geographic Area Types U.S. and Puerto Rico

Type of Geographic AreaTotal

Number of Areas

Percent of Areas with a Population of 65,000 or more

Percent of Areas with a Population of 20,000 or more

States, District of Columbia, and Puerto Rico

52 100 100

County or equivalent 3,221 26 59

Congressional Districts 435 100 100

Public Use Microdata Areas 2,101 100 100

Metropolitan and Micropolitan Statistical Areas

955 55 98

http://www.census.gov/acs/www/data_documentation/areas_published/

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Hierarchy of Census Geographic Entities

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Overview

• Basic Census Bureau geography

• Geographic areas for which ACS data are available

• Geographic area concept and definition issues to be aware of when using ACS data

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Tracts and Block Groups

• Census tracts are small, relatively permanent statistical subdivisions of a county

• Block groups are statistical subdivisions of census tracts and are the lowest level of geography available in the ACS

• Block group estimates are available only in the ACS Summary File, not American FactFinder

• Block groups and tracts are available only in the ACS 5-year estimates

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Kalamazoo County, MI -Census Tract 30.04

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Kalamazoo County, MI - Census Tract 30.04, Block Groups 1, 2, & 3

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ZIP Code Tabulation Areas

• First available in the 2007-2011 ACS 5-year estimates

• Abbreviated form-ZCTAs

• Similar to U.S. Postal Service ZIP codes

http://www.census.gov/geo/reference/zctas.html

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County SubdivisionsMinor Civil Divisions and Census County Divisions

• Minor Civil Divisions (MCDs) – Legally bounded entity– Sub-county entities in 29 states, the District of

Columbia, and Puerto Rico– May have a local government with elected

officials

• Census County Divisions (CCDs) – Statistical entity– Sub-county units that have stable boundaries and

recognizable names in 21 states– No minimum or maximum population guidelines– Not included in ACS 1 or 3 year data products

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County SubdivisionsDistribution Map of MCDs and CCDs

TN

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PlacesIncorporated Places and Census Designated Places

• Incorporated Places– Legally bounded entity– Referred to as cities, boroughs, towns, or

villages, depending on the state

• Census Designated Places (CDPs)– Statistical entity– Created to present census data for an area with a

concentration of population, housing, and commercial structures that is identifiable by name, but not within an incorporated place

– Examples: Columbia, MD; Paradise, NV

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PlacesSalem County, New Jersey

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PlacesMendocino County, California

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Urban AreasUrbanized Areas and Urban Clusters

• Urbanized Areas– 50,000 or more people

• Urban Clusters – 2,500 up to 49,999 people

• Both defined after each decennial census

• 2012 ACS Estimates and subsequent ACS estimate years will reflect Urban Areas defined using the 2010 Census results

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Rural Areas

• All territory not within an urban area

• Cuts across other hierarchies

• Can be in metropolitan or non-metropolitan areas

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Urban AreasUrbanized Areas and Urban Clusters in Tennessee

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Metropolitan and Micropolitan Statistical Areas

• Defined by U.S. Office of Management and Budget

• Metropolitan Statistical Areas– Contains core Urban Area of 50,000 or more population– Its own County, and– Surrounding counties with heavy commuting patterns

• Micropolitan Statistical Areas– Contains urban core between 10,000 – 49,999 population– Only small percentage have population 65,000 or more

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Metropolitan and Micropolitan Statistical Areas-Map

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Partial Map of Virginia Metropolitan Statistical Areas, Urban Areas, Places

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Public Use Microdata Areas (PUMAs)

• Minimum population of 100,000

• Cannot cross state boundaries

• Composed of:– Census tracts– Places (excluded for the new PUMA

definitions)– One or more Counties – Combination of Tracts and Counties

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Public Use Microdata Areas

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Overview

• Basic Census Bureau geography

• Geographic areas for which ACS data are available

• Geographic area concept and definition issues to be aware of when using ACS data

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Geographic Boundaries

• Multiyear estimates are based on geographic boundaries as of January 1 of the last year in the multiyear period

• Legal area changes are recorded in the Boundary and Annexation Survey (BAS)

• Statistical areas are updated every decade in conjunction with the decennial census

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Geographic BoundariesAmarillo city, TX

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Geography Notes

• Release notes available for each year at http://www.census.gov/acs/www/data_documentation/geography/

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Additional ACS Resources

• ACS website (census.gov/acs)

• American FactFinder (factfinder2.census.gov)

• QuickFacts (quickfacts.census.gov)

• DataFerrett (dataferrett.census.gov)

• FAQs (https://ask.census.gov/faq.php?id=5000&rtopic=1805)

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Final Thoughts

• The U.S. Census Bureau measures the nation’s People, Places and Economy

• Census Bureau statistics are how America knows what America needs

• The Census Bureau is the leading source of quality, timely and relevant information about our nation’s people and economy

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Contact Information

Subscribe to “Email Updates”http://www.census.gov/acs

Visit the ACS/PRCS website:http://www.census.gov/acs

Contact by Telephone:1-800-923-8282

Submit a Question:https://ask.census.gov

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