The lowest level of geography for summary data from 1970 is either block groups (in areas were tracts were defined) or elsewhere enumeration districts (ED). This overview outlines how key products were originally published and highlights only a few of the custom products that were subsequently produced based on the original.

Note that some sample questions were asked of either a 15% or a 5% sample of households, but some were asked for both, thus constituting a 20% sample. Variation can occur among totals based responses from 20%, 15% or 5% samples.

• Summary Files
  The table below outlines the most commonly used summary files from the 1970. Not all these files are readily available. For some that are all states may not be reported.

• Other Summary File Products
  Special subsets based on either geography or topic have been created from the Summary Files. When needs can be met with these files, they are easier to use than the original files. Also there are the Elizabeth Bogue Census Tract Files for which data was keyed in from the printed tract reports for selected metropolitan areas.
• Public Use Microdata
  Public Use Microdata were produced and reported for county groups, states, and geographic divisions with neighborhood characteristics each with a population of at least 250,000. Originally the files were hierarchical (contain both household and person records). A modified version is also available that combines household and person data on record so that the file is rectangular.
• Maps
  Columbia's holdings for 1970 maps are described on the Government Documents 1970 Decennial Census Information web page.

• Files for FTP
  If using the ascii versions of the summary files, users should acquaint themselves with how certain Technical Issues are handled. Suppression and allocation are issues of particular interest to those dealing with tract level or smaller geographies.
  • ICPSR
    Provides the most complete archive of 1970 files including a number of special extractions produced by the Census Bureau for easier access for some geographic areas and the Elizabeth Bogue tract data files for selected metropolitan areas (does not include NYC).
  • CU Data Catalog
    Selected files (especially for New York City counties) are available. Search the data catalog for study number 1970 to see what is available.
• Online Extraction Data
  • Social Explorer
    Use Data & Tools then choose Browse Reports to obtain selected tables for years including 1970.
    
  • National Historical Geographic Information System (NHGIS)
    NHGIS provides an online extraction tool for selected summary file variables at the national, state, county, and tract/block numbering areas allowing for multiple locations at one level of geography to be downloaded at once
  • Longitudinal Tract Data Base (LTDB)
    Preselected 1970 population characteristics in Excel spreadsheets reported for tracts as defined in 1970 or as defined in 2010. LTDB also has a feature that allows you to adjust any data based on 1970 tracts to estimates based on 2010 tracts.
  • Integrated Public Use Microdata Series (IPUMS)
    At this site custom extractions of public use microdata can be done. Coverage is for all census years since 1850 except 1930.
• Spatial Data
  
  • National Historical Geographic Information System (NHGIS)
    NHGIS is a project to create and freely disseminate a database incorporating all available aggregate census information for the United States between 1790 and 2000. You can download tract boundary files by state.

• 1970 Census CU Libraries Holdings
  This is a detailed list of Columbia's print and CD-ROM holdings plus links to useful websites and reference sources.
• Obtaining Data by Congressional District
• Historical Census Data Tables
  The Census Bureau has published a number of tables covering all census years. In addition to basic counts of people and housing, there are selected special topics included.
• National Archives and Records Administration (NARA)
  Together with listing of their electronic holdings (which are available at cost), the NARA provides descriptive information about each file.
• Comparing 1970 and with other Census years
  • Significant Changes to Counties: 1970-Present
    Summarizes the changes to boundaries for counties or county equivalent areas deemed to be significant because of either population affected or land area involved.
  • Historical Metropolitan Area Definitions (1999 and earlier)
• Related reference material
  • Geographic Areas Reference Manual
    Although focused on the 1990 Census this book provides a history of census geography and including information about areas like, MCDs, CCDs, outlying areas, Indian lands, and blocks. This book is also available in print in the Data Service and in CLIO.
  • Measuring America: The Decennial Censuses From 1790 to 2000
    Contains questionnaires and instructions, plus individual histories of each census as well as a chart listing topics covered in each census year. This book is also available in print in the Data Service and in CLIO.
• Decennial Census: General Census Monographs
  This is a list of other publications on the subject of the Decennial Census.