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Census Geographic Areas (Small-Area Geography)

  • Census Geographic Areas (Small-Area Geography)

    Blocks
    • Smallest units of data tabulation.
    • Generally bounded by visible features and legal boundaries.
    • Block numbers completely different from 1990.
    • Size: average about 100 people.

    Block Groups

    • Groups of blocks sharing the same first digit
    • Smallest areas for which sample data available
    • Size: optimally 1,500 people, range between 300 to 3,000
    Census Tracts
    • Seamless national coverage
    • Relatively homogenous population characteristics
    • 65,000 Census tracts across U.S.
    • Size: optimally 4,000 people, range between 1,000 and 8,000

    small-area census geography

     

    census geographic hierarchy

     

 


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