Data Availability

Summary tables
Time series tables
GIS files
Geographic crosswalks

Summary tables

NHGIS includes summary tables from all U.S. decennial censuses, from the American Community Survey, and from a selection of other sources.

Highlights:

  • Decennial census data (1790-2020)
    • County and state tables since 1790
    • Census tract tables since 1910
    • Tables for all original census summary levels, down to census blocks, since 1970
  • American Community Survey data
    • 5-year periods from 2005-2009 through 2016-2020
    • 1-year periods from 2010 through 2019
      • The only 2020 ACS 1-year summary data published by the Census Bureau are the Experimental Data Tables, specially designed to address deficiencies in the 2020 sample due to the COVID-19 pandemic. NHGIS has not added the Experimental Data Tables because they include only nation- and state-level data for a smaller range of subjects than standard 1-Year Summary Files.
  • County Business Patterns data (1970-2002, annual)
  • Vital statistics
    • Birth and death data for counties and states (1915-2007, annual)
    • Marriage and divorce data for counties (70 years between 1867 and 2010)
  • Agricultural census data (1840-1950)
  • Religious bodies data (1850-1952)
  • Manufacturing census data (1840-1940)
  • 2010 Census data for SABINS school attendance areas
  • Environmental summaries*
    • Land cover for counties and census tracts (2001, 2006, 2011)
    • Precipitation and temperature for counties (1895-2014)

The NHGIS Data Finder allows users to explore which tables are available by geographic level, by year, by topic, and/or by source dataset.

More details:

*The environmental summaries are not available via the Data Finder. Users may download them directly from the Environmental Summaries page.

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Time series tables

NHGIS time series tables cover a range of basic 100%-count statistics from the 1970-2020 censuses as well as several popular sample-based statistics from the 1970-2000 long-form surveys and from American Community Survey 5-Year Summary Files for 2008-2012 and 2015-2019. There are also tables of state and county data that go back to 1790 for Total Population and back to 1820 for Persons by Sex.

Nominally integrated time series tables, which align geographic units across time by matching names and codes without regard to boundary changes, cover up to 8 geographic levels ranging from the nation down to census tracts. The set of covered levels varies among tables according to which statistics are available for each level in each source year.

Geographically standardized time series tables, which provide estimates for a single year's geographic units by interpolating data from other years, cover 1990, 2000, 2010, and 2020 100%-count statistics for 2010 geographic units at 10 geographic levels ranging from states down to block groups.

To see all topics for which time series are available, open the Topics filter window through the NHGIS Data Finder and look for topics marked with the "TS" icon.

Details for all available time series tables:

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GIS files

The table below summarizes the geographic units and years covered by NHGIS shapefiles. Note that the extent of coverage may vary among geographic units and across years. For example, census tracts covered only 8 cities in 1910 and did not cover the entire U.S. until 1990. More detailed coverage information is provided through the links in the table.

The years in the table generally identify the survey years for which the units were used in tabulations, which may differ from the vintages of the units. For example, 2011 NHGIS boundary files represent areas used in 2011 American Community Survey tabulations, including 2009 Core Based Statistical Areas and 2000 Public Use Microdata Areas.

Unless otherwise noted, the basis for 2000 and all earlier NHGIS boundaries is the 2000 TIGER/Line files, and the basis for 2010 and later years' boundaries is the TIGER/Line release of the same year.

More information on GIS file years and sources is provided here.

GIS File Availability by Geographic Unit and Year
Primary Census Divisions 2020 2012-2019 2011 2010 2009 2000 1990 1980 1950-1970 1910-1940 1790-1900
Nation X X X Xm X Xa          
Region X X X Xm X Xa          
Division X X X Xm X Xa          
State [map] [list] X X X Xm X Xb X X X X X
County [map] [list] X X X Xm X Xc Xd Xd Xd Xd Xd
Census Tract [map] [list] [interactive map] X X X Xm * Xc Xd Xd Xd Xd  
Block Group X X X Xm * Xb X        
Block X     Xm   Xb X Xe,n      
Civil / Urban / Metropolitan Units 2020 2012-2019 2011 2010 2009 2000 1990 1980 1950-1970 1910-1940 1790-1900
County Subdivision X X X Xm X Xb X Xe      
Subminor Civil Division [map] X X X Xm   Xa          
Place (Boundary Files) [map] [interactive map] X X X Xm X Xb X Xe      
Place (Point Files)   Xl X X X X X X X X 1900
Consolidated City [map] X X X Xm X Xa          
Urban Area [map] X X   X X X X        
Core Based (Metropolitan/Micropolitan) Statistical Area X X X X X            
Metropolitan Division X X X X X            
Combined Statistical Area X X X X X            
Metropolitan Statistical Area/
Consolidated Metropolitan Statistical Area [map]
          X X        
Primary Metropolitan Statistical Area           X X        
Standard Metropolitan Statistical Area [map]               X X    
Standard Consolidated Statistical Area [map]               X      
New England City and Town Area [map] X X X X X            
New England City and Town Area Division X X X X X            
Combined New England City and Town Area [map] X X X X X            
New England County Metropolitan Area [map]           X X        
Legislative / Electoral Units 2020 2012-2019 2011 2010 2009 2000 1990 1980 1950-1970 1910-1940 1790-1900
Congressional District [map] X Xf X Xm X Xb X        
State Legislative District (Upper Chamber) [map] X X X Xm X Xa          
State Legislative District (Lower Chamber) [map] X X X Xm X Xa          
Voting District [map] X Xk   X   Xb X        
School Units 2020 2012-2019 2011 2010 2009 2000 1990 1980 1950-1970 1910-1940 1790-1900
School District (Elementary) [map] X X X Xm X Xa          
School District (Secondary) [map] X X X Xm X Xa          
School District (Unified) [map] X X X Xm X Xa          
SABINS School Attendance Area [map]     Xg Xg Xg            
Native American / Alaskan / Hawaiian Units 2020 2012-2019 2011 2010 2009 2000 1990 1980 1950-1970 1910-1940 1790-1900
Alaska Native Regional Corporation X X X Xm X Xa          
American Indian Area/Alaska Native Area/Hawaiian Home Land [map] X X X Xm X Xb X        
American Indian Area/Alaska Native Area (Reservation or Statistical Entity Only) X X X Xm X Xa          
American Indian Area (Off-Reservation Trust Land Only)/Hawaiian Home Land X X X Xm X Xb          
Tribal Subdivision X X X Xm X Xb          
Tribal Census Tract X X X X              
Tribal Block Group X X X X              
Other Units 2020 2012-2019 2011 2010 2009 2000 1990 1980 1950-1970 1910-1940 1790-1900
5-Digit ZIP Code Tabulation Area X X   Xm   Xb          
Public Use Microdata Area (PUMA) X X Xh Xh X X          
Centers of Population 2020 2012-2019 2011 2010 2009 2000 1990 1980 1950-1970 1910-1940 1790-1900
State X     X   X          
County X     X   X          
Census Tract X     X   X          
Block Group X     X   X          

Table notes:
a. Based on 2010 (not 2000) TIGER/Line features
b. 2 versions based on 2000 or 2010 TIGER/Line features
c. 3 versions based on 2000, 2008, or 2010 TIGER/Line features
d. 2 versions based on 2000 TIGER/Line features or conflated to 2008 TIGER/Line features
e. Based on 1992 (not 2000) TIGER/Line features
f. 2012 boundaries for congressional districts are based on features from the special 113th Congress TIGER/Line release (not 2012 TIGER/Line features)
g. Boundaries available for 2009-2010, 2010-2011, and 2011-2012 school years. All are based on 2010 TIGER/Line features, and corresponding tabular data is derived from the 2010 Census.
h. Based on 2000 TIGER/Line features. (Not available in 2010 or 2011 TIGER/Line source files.)
i. 4 versions based on 2000, 2008, 2009, or 2010 TIGER/Line features
j. 3 versions based on 2000, 2009, or 2010 TIGER/Line features
k. Available for 2012 basis only. (Not available in later TIGER/Line source files.)
l. Not available for 2016 or later years
m. 2 versions based on 2010 or 2020 TIGER/Line features
n. Current version covers only selected metropolitan areas. Future versions will cover more areas. Files are provided through the 1980 Block Boundaries page, not yet through the Data Finder.
* Census tract and block group boundaries derived from the 2009 TIGER/Line files are available, but NHGIS identifies these boundaries with 2000, not 2009, because they do not completely correspond to the units used in 2009 ACS tables. More information is available here.

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Geographic crosswalks

NHGIS geographic crosswalk files describe how U.S. census geographic units from one census year correspond to units from another year, facilitating tabulations of one year's data for another's geographic units. Currently, NHGIS provides crosswalks for these years and geographic levels:

Crosswalk Availability by Geographic Levels and Years
Source Zones Target Zones 1990 to 2010 2000 to 2010 2010 to 2020 2020 to 2010
Blocks Blocks X X X X
Block Group Parts Block Groups X X    
Block Group Parts Census Tracts X X    
Block Group Parts Counties X X    
Block Groups Block Groups     X X
Block Groups Census Tracts     X X
Block Groups Counties     X X


The crosswalks are not available via the Data Finder. Users may download them directly from the Geographic Crosswalks page.

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