Blocks

• Smallest units of data tabulation

• Cover the entire nation

• Do not cross census tracts or counties

• Generally bounded by visible features and legal boundaries

• Block numbers completely different from 1990

• Size: average about 100 people

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A block is defined as an area bounded on all sides by visible and/or invisible features shown on a map prepared by the U.S. Census Bureau. A block is the smallest geographic entity for which the Census Bureau tabulates decennial census data.

There are about 8,200,000 blocks delineated for Census 2000.

There has been a complete renumbering of blocks across the U.S. One other major change is that the numbering has gone from a three-digit system to a four-digit system. Water bodies were also assigned block numbers in Census 2000 for the first time.

Speaker Note: The Census Bureau used different “collection block numbers” for the precensus period and collection of data. For delineation purposes different “tabulation block numbers” have been assigned. Block numbers for the precensus and census activities ignored many legal boundaries, whereas for data tabulation, the Census Bureau held every tabulation area boundary as a block boundary. Basically, tabulation area boundaries are those block boundaries taken as a snapshot of geography on January 1, 2000.