Census Tracts and Block Numbering Areas
Census tracts are small, relatively permanent statistical subdivisions of
a county. Census tracts are delineated for most metropolitan areas (MA's)
and other densely populated counties by local census statistical areas
committees following Census Bureau guidelines (more than 3,000 census
tracts have been established in 221 counties outside MA's). Six States
(California, Connecticut, Delaware, Hawaii, New Jersey, and Rhode Island)
and the District of Columbia are covered entirely by census tracts.
Census tracts usually have between 2,500 and 8,000 persons and, when first
delineated, are designed to be homogeneous with respect to population
characteristics, economic status, and living conditions. Census tracts do
not cross county boundaries. The spatial size of census tracts varies
widely depending on the density of settlement. Census tract boundaries
are delineated with the intention of being maintained over a long time so
that statistical comparisons can be made from census to census. However,
physical changes in street patterns caused by highway construction, new
development, etc., may require occasional revisions; census tracts
occasionally are split due to large population growth, or combined as a
result of substantial population decline. Census tracts are referred to
as "tracts" in all 1990 data products. Block numbering areas (BNA's) are
small statistical subdivisions of a county for grouping and numbering
blocks in non-metropolitan counties where local census statistical area
committees have not established census tracts. More information is
available in the Geographic Areas
Reference Manual. (PDF)
Changes for Census 2000 include the following:
- The census tract and BNA programs will merge into a single program and
the geographic entity will be called a census tract.
- Census tracts will be delineated by local participants as part of the
Census Bureau's Participant Statistical Areas Program. The Census Bureau
will delineate census tracts in situations where no local participant
could be found or where local or tribal governments declined to
participate.
- Census tract population criteria will be 1,500 to 8,000 persons.
- Census 2000 Plans
The "Participant Statistical Area
Program
- 1990 Census Tracts
- Products
- Federal Program Information
Federal Programs Using Census Tract
Data
Federal
Depository Libraries (research resource)
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Source: U.S. Census Bureau, Geography Division
Created: April 19, 2000
Last Revised: November 14, 2000 at 11:43:15 AM
