Census Data: Decennial Census

What is the Decennial Census?

The federal government conducts a full count of the US population every ten years, starting in 1790.  Questions change every decade, but there is always some information about every individual in every household as well as some information about housing conditions.

Decennial Census data is available from a variety of sources and comes as aggregated (or summary) totals or microdata.

Aggregated data are totals by subject (such as race or age) and geography and microdata refers to individual survey responses. 

Aggregated Data

There are many sources for Decennial Census data.  Here are a few that we recommend:

For researchers in a hurry:

Social Explorer 

  • What can you get - Social Explorer contains variable summaries from every census from 1790 (there are other data resources available as well)
  • What works well - Social Explorer has a relatively easy interface and table builder for creating data extracts.  There is also a map-based data browse interface for data exploration and simple map making. 
  • What does not work well - Selection is limited in the category browser.  Limited to current Columbia Affiliates (or other paying customers).

PolicyMap 

  • What can you get - Summaries for some variables from the 2000 Census forward
  • What works well -  Relatively easy to build tables or create a map of a single variable at a time.
  • What does not work well - Limited to current Columbia Affiliates (or other paying customers), difficult to create downloads or multiple variables.  Not all geographies are available. 

 

For detailed information and tables:

Census Advanced Search

  • What can you get - Variable summaries and crosstabs for all geographies for censuses starting in 2000
  • What works well - Contains cross tabs and pre-made tables of popular variables. Free for all to use. 
  • What does not work well - Interface is difficult, only recent data available (mostly post 2000). 

National Historical GIS (For historical and longitudinal research)

  • What can you get - Variable summaries from every census from 1790 at a wide variety of geographies, along with corresponding geospatial files for mapping and spatial analysis
  • What works well - Relatively easy to use table builder. Can build tables for a variety of years at once. Free for all to use.  Historical GIS boundary files are available (assumes knowledge of GIS software). 
  • What does not work well - Not all variables and crosstabs are available from the category browser. 

Longitudinal Tract Data Base

  • What can you get - Data from 1970 forward with estimates provided at current (2020) boundaries. 
  • What works well - Provides a through line to account for variability in fifty years of Census geographies, questions, and possible answers.
  • What does not work well - Not the most efficient solution unless your focus is historical change over time through longitudinal comparison. Note that data are estimates. 

 

Microdata

IPUMS USA

  • What can you get - samples from every census from 1790 (including complete count data for 1790-1940).
  • What works well   - the most comprehensive resource for creating microdata samples, free and relativley easy to use
  • What does not work well - this is a strongly reccommended resources, however this process is inherently complex.  Note that there are tutorials available on Youtube

Data.census.gov also has a microdata portal in beta version

  • What can you get  - Samples from 2010 forward
  • What works well
  • What does not work well

AncestryLibrary.com

  • What can you get  - Scanned survey sheets from historical censuses from 1790-1950
  • What works well
  • What does not work well - This is not a resource for extracting datasets, but rather a genalogical tool for finding information on individuals and households.

 

Nerd Section

Decennial Census data is available from a variety of resources, however you may want to consult the Technical documentation for the Census, including the survey instruments and questionnaires for all censuses since 1790.