United States Census Data

The U. S. Census uses  many spatial units to analyze and aggregate data.  Below are examples of the different units available through NHGIS, listed in order of scale:

SEE ALSO Note on using Spatial Data

• Nation
• Region
• Division
• State
• Combined Statistical Areas*
• County
• Public Use Microdata Areas (PUMAs)*
• ZIP Codes
• School Districts
• Voting Districts
• Tracts
• Block Groups
• Blocks

*Units marked with an asterisk may be larger than, or cross boundaries of larger scale units

NOTE that many spatial units can be aggregated to larger levels.  Zone Improvement Plan (ZIP) Codes  and school districts may be excepted

About : The United States is divided into four regions:  Northeast , South, Midwest, and West (including Alaska and Hawaii).

• Region 1 (Northeast) : Maine, Massachusetts, New Hampshire, Vermont, Connecticut, Rhode Island, New York, Pennsylvania New Jersey
• Region 2 (Midwest) : Ohio, Michigan, Indiana, Illinois, Iowa, North Dakota, South Dakota, Nebraska, Kansas, Missouri, Wisconsin, Minnesota
• Region 3 (South) : Maryland, Delaware, West Virginia, District of Columbia, Virginia, Kentucky, North Carolina, South Carolina, Georgia, Florida, Tennessee, Alabama, Mississippi, Louisiana, Arkansas, Oklahoma, Texas.
• Region 4 (West) : Alaska, Hawaii, Washington, Oregon, California, Arizona, New Mexico, Colorado, Utah, Idaho, Wyoming, Montana.

Spatial Scope : United States and the District of Columbia.  Does not include Puerto Rico other territories and dependencies.

Use:  Regions are used as analytic units in: 

• American Community Survey (ACS)
• American Housing Survey (AHS)
• Annual Business Survey (ABS) (formerly SBO)
• Behavioral Risk Factor Surveillance System (BRFSS)
• Business Dynamics Statistics (BDS)
• Commercial Buildings Energy Consumption Survey (CBECS)
• Consumer Expenditure Survey (CEX) (regional tables)
• County Business Patterns (CBP) (summary tables)
• Current Population Survey (CPS)
• CPS ASEC (Annual Social and Economic Supplement)
• CPS Fertility Supplement
• CPS Health Insurance Supplement
• CPS School Enrollment Supplement
• CPS Voting & Registration Supplement
• Decennial Census of Population and Housing
• Economic Census (summary outputs)
• Household Pulse Survey (HPS)
• National Health and Nutrition Examination Survey (NHANES)
• National Health Interview Survey (NHIS)
• National Household Education Surveys (NHES)
• National Household Travel Survey (NHTS)
• National Survey of Family Growth (NSFG)
• National Vital Statistics System (NVSS)
• Nonemployer Statistics (NES)
• Population Estimates Program (PEP)
• Population Projections (Census Bureau)
• Quarterly Workforce Indicators (QWI) (selected aggregates)
• Residential Energy Consumption Survey (RECS)
• Small Area Income and Poverty Estimates (SAIPE)
• Survey of Business Owners (SBO) (now ABS)
• Survey of Consumer Finances (SCF)
• Survey of Income and Program Participation (SIPP)

About : The United States is divided into nine divisions. 

• Division 1 (New England) : Maine, New Hampshire, Vermont, Massachusetts, Rhode Island, Connecticut
• Division 2 (Middle Atlantic) : New York, New Jersey, Pennsylvania
• Division 3 (East North Central) : Ohio, Indiana, Illinois, Michigan, Wisconsin
• Division 4 (West North Central) : Minnesota, Iowa, Missouri, North Dakota, South Dakota, Nebraska, Kansas
• Division 5 (South Atlantic) : Delaware, Maryland, District of Columbia, Virginia, West Virginia, North Carolina, South Carolina, Georgia, Florida
• Division 6 (East South Central) : Kentucky, Tennessee, Alabama, Mississippi
• Division 7 (West South Central) : Arkansas, Louisiana, Oklahoma, Texas
• Division 8 (Mountain) : Montana, Idaho, Wyoming, Nevada, Utah, Colorado, Arizona, New Mexico
• Division 9 (Pacific) : Alaska, Washington, Oregon, California, Hawaii

Spatial Scope : United States and the District of Columbia.  Does not include Puerto Rico other territories and dependencies.

Use: 

• Decennial Census of Population and Housing
• American Community Survey (ACS)
• American Housing Survey (AHS) 
• Business Dynamics Statistics (BDS)
• County Business Patterns (CBP)
• Current Population Survey (CPS)
•     CPS Annual Social and Economic Supplement (ASEC)
•     CPS Voting & Registration Supplement
•     CPS School Enrollment Supplement
•     CPS Health Insurance Supplement
• Economic Census
• Household Pulse Survey – published briefings often compare changes by division
• National Health Interview Survey (NHIS) – published trend tables by region/division
• National Health and Nutrition Examination Survey (NHANES) – uses divisions in weighting and analytic groupings
• National Vital Statistics System (NVSS) – mortality and birth reports often include division-level summaries
• National Household Education Surveys (NHES)
• Non-employer Statistics (NES) – some national tables group by division
• Population Estimates Program (PEP)
• Population Projections (Census Bureau)
• Quarterly Workforce Indicators (QWI, LEHD program) – in selected aggre
• Small Area Income and Poverty Estimates (SAIPE)
• Small Area Health Insurance Estimates (SAHIE)
• Survey of Business Owners (SBO) / Annual Business Survey (ABS)
• Survey of Income and Program Participation (SIPP)
   

About : Almost all Census Bureau reports and other statistical reports from government sources area aggregated at the level of the state.  Some Government reports include Territories and dependencies like Puerto Rico, Guam, North Marianas Islands, and American Samoa as well.

Spatial Scope : United States and the District of Columbia.  Does not include Puerto Rico other territories and dependencies.

Uses:

• American Community Survey (ACS)
• American Housing Survey (AHS) (state-level for selected states/metros depending on sample design)
• Annual Business Survey (ABS) (formerly SBO)
• Behavioral Risk Factor Surveillance System (BRFSS)
• Business Dynamics Statistics (BDS)
• Commercial Buildings Energy Consumption Survey (CBECS) (some state-level releases depending on sample)
• Consumer Expenditure Survey (CEX) (selected state-level stats published)
• County Business Patterns (CBP) (includes state totals)
• Current Population Survey (CPS) (state identifiers in microdata; many published tables by state)
• CPS ASEC (Annual Social and Economic Supplement)
• CPS Fertility Supplement
• CPS Health Insurance Supplement
• CPS School Enrollment Supplement
• CPS Voting & Registration Supplement
• Decennial Census of Population and Housing
• Economic Census (state-level economic data is standard)
• Household Pulse Survey (HPS)
• National Health and Nutrition Examination Survey (NHANES) (state-level only in limited releases- primarily national or regional, but some state pilot data exists)
• National Health Interview Survey (NHIS) (state-level estimates in some years; microdata contains state identifiers for research files)
• National Household Education Surveys (NHES) (state estimates in selected years/reports)
• National Household Travel Survey (NHTS) (state-level in selected datasets)
• National Survey of Family Growth (NSFG) (microdata contains state-level coding for some public-release cycles)
• National Vital Statistics System (NVSS) (births, deaths, marriages, fetal deaths are fully state-level)
• Nonemployer Statistics (NES)
• Population Estimates Program (PEP) (annual state population estimates)
• Population Projections (Census Bureau)
• Quarterly Workforce Indicators (QWI) (state-level is core geography)
• Residential Energy Consumption Survey (RECS) (state-level in selected years)
• Small Area Health Insurance Estimates (SAHIE) (state + county — YES at state-level)
• Small Area Income and Poverty Estimates (SAIPE) (state + county — YES at state-level)
• Survey of Business Owners (SBO) (now ABS)
• Survey of Consumer Finances (SCF) (state not always published; microdata suppressed, but regional/state-coded internally)
• Survey of Income and Program Participation (SIPP) (state available in microdata in some years)

Figure above : Detail of the Baltimore and Washington Region PUMAs

About : Public Use Microdata Areas (PUMAs) are a special type of Census Bureau geographic unit that defines areas for which individual-level (microdata) records can be released to the public while protecting confidentiality. Each PUMA is built from one or more contiguous census tracts and contains a population of at least 100,000 people, which is large enough that individuals cannot be easily re-identified from the detailed household and person records in datasets like the American Community Survey (ACS) Public Use Microdata Sample (PUMS). PUMAs are wholly within a single state, but within a state they can cross county, city, and other local boundaries in order to meet the population threshold or reflect functional community areas. 

Spatial Scope :  There are 2486 PUMAs in 50 United States and the District of Columbia. Does not include Puerto Rico other territories and dependencies.

Use:

American Community Survey (Select Reports) 
Decennial Census, Public Use Microdata Sample (PUMS)
Housing Needs Assessments

Figure above : Detail of Maryland counties.

About : The U.S. Census aggregates almost all data observations at the level of county.  This includes sub-state units like Parishes in Louisiana, Boroughs in Alaska, and Planning Regions in Connecticut.

Spatial Scope : 3,221 Counties and other sub-state administrative units in the United States and the District of Columbia.  Does not include Puerto Rico other territories and dependencies.

Use :  Many Census Bureau data reports and other government data reports aggregate data at the level of the county.

Figure above : Detail of ZIP codes in Baltimore region.

About : NHGIS provides select census data at ZIP code geographies.  Please NOTE that the ZIP codes are produced by the United States Postal Service and may not be coterminous with census geographies.

Spatial Scope :  33,774 ZIP codes in 50 United States and the District of Columbia. Does not include Puerto Rico other territories and dependencies.

Figure above : detail of voting districts in Baltimore City

About : NHGIS provides voting district geographies for 1990, 2000, 2010, 2012, and 2020 along with select demographic variables

Spatial Scope : 158,282 voting districts in the United States and the District of Columbia for 2020.  Does not include Puerto Rico other territories and dependencies.

About : The United States is divided into 85,074 tracts.  A detail of Baltimore City is shown above.

Spatial Scope : 50 United States, the District of Columbia and Puerto Rico.

Use:  Tracts are used as analytic units in the Decennial Census, American Community Survey (ACS), Current Population Survey (CPS), Economic Census, Survey of Business Owners (SBO), and the Population Estimates Program.

About : The United States is divided into 242,180 block groups in 2020.  A detail of Baltimore City is shown above.

Spatial Scope : 50 United States, the District of Columbia and Puerto Rico.

Use:  Census block groups are used as analytic units in the Decennial Census, American Community Survey (ACS), Current Population Survey (CPS), Economic Census, Survey of Business Owners (SBO), and the Population Estimates Program.

About : Census blocks are the smallest spatial analytic unit produced by he U. S. Census Bureau. The United States is divided into 8,180,866 blocks in 2020.  A detail of Baltimore City is shown above.

Spatial Scope : 50 United States, the District of Columbia and Puerto Rico.

Use:  Census block groups are used as analytic units in the Decennial Census, American Community Survey (ACS), Current Population Survey (CPS), Economic Census, Survey of Business Owners (SBO), and the Population Estimates Program.