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