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Census Data

Every 10 years, the United States government is required to count all of its citizens. This is a guide to the Decenniel Census. The government not only tries to count all of us, but also gather different types of data about all of us.

A Short History of the Census

Purposes of the Census and its Geography

  1. "... provide the most complete and accurate population count possible for apportionment ..."
  2. Redistricting for congressional and legislative purposes.
  3. Track economic and social trends.
  4. Distribution of public funds.
  5. Administration of public and private programs
  6. FAQ's about Census Geography

Categories for Census Geography

  1. Legal - Nation, States
  2. Administrative - School districts, zip codes
  3. Statistical - Regions, MSA's
  4. Glossary for Census Geography

When did it start

  1. Counties are an English tradition
  2. First census - 1790
  3. Small geography areas based on population, topography and housing first appeared in 1890.
    • Census Office
    • Sanitary districts
    • Create a network of these small geographic areas around the country

History of Census Tracts

  1. 1906 - Walter Laidlaw and the Population Reseach Bureau of the New York Federation of Churches
  2. 1909 - Laidlaw made his proposal to the Census Office
  3. 1910 - Census Office designated 8 cities with delineated districts
    • Laidlaw divided New York City into districts
    • The data would be available for purchase!

More History of Census Tracts

  1. The Census Office collected delineated data for these cities in 1910 and 1920.
  2. Only New York City used the data immediately.
  3. Mid 1920's - Chicago and Cleveland purchased their data and published it.
  4. 1929 - 18 cities reviewed or delineated new tracts for 1930.

A Little More History

  1. Howard Whipple Green
    • Statistical consultant, Cleveland, OH
  2. American Statistical Association
    • Committee on Census Enumeration Areas
  3. 1940 - Census Bureau officially adopted the census tract
  4. 1955 - Howard W. Green retired and the Census Bureau controlled promotion and coordination.

Importance of Census Geography

  1. Census Geography nests
  2. The geography does not cross established boundaries
  3. Block Numbering Areas (BNA's) covered areas without tracts
  4. BNA's became statistically equivalent to tracts with the 1990 Census
  5. Tracts became universal within the U.S. only with the 2000 Census

ZIP Code Geography

  1. ZIP code geography is separate from Census geography
  2. The U.S. Postal Service (USPS) created and control these boundaries
  3. They do not follow the same conventions as Census geography
    • Cross legal, administrative and statistical boundaries
    • Are not always completely enclosed
  4. Census Bureau created 1990 and 1999 ZIP code files on an "as is" basis


  1. ZCTA's - ZIP Code Tabulation Areas
  2. Created by the Census Bureau
  3. Similar to ZIP Code boundaries but not an exact match
  4. File updated to 2002
  5. No further updates planned until the 2010 Census.


Other Resources for Census Geography

  1. Census 2010 Geographic Terms & Concepts
  2. Census Bureau Map Products
  3. U. S. Census Gazetteer Files
    1. Files the Census Bureau created to help people locate places without knowing longitude and latitude.
    2. Separate files for Places, Counties, County Subdivisions, Census Tracts and ZCTA's.
    3. Each record in the file contains FIPS numbers, latitude and longitude, area in square miles and meters, total population and total housing units.
    4. The files are in ASCII text format.

Sources: United States. Bureau of the Census. . Updated on May 24, 2016.
American Factfinder. . Updated on May 24, 2016.