About this Guide
This research guide describes some of the major print and electronic
resources for finding Census statistical information from the 1990, 2000, and 2010 Decennial Census.
In addition, there is information on Census tracts, Census tract numbers for Pittsburgh and Alleghany County, and mapping. Furthermore basic steps on how to use American Factfinder to generate demographic information is also included.
For further information on these resources or to schedule a research consultation, contact the Coordinator of Government Publications, Mark Scott or Government Information Librarian, Tom Twiss (Contact information is in the box on the right of this page.)
Why the Federal government takes a Census
According to the United States Constitution, Article I, Section 2 mandates that an apportionment of the representative among the states, for the U.S. House of Representatives, be carried out every 10 years (decennially).
Apportionment is the process of dividing the 435 seats in the U.S. House of Representatives among the 50 states. Using equal portions, each state is assigned one congressional seat (as provided by the Constitution). The apportionment formula then allocates the remaining 385 seats one at a time among the 50 states until all 435 seats are assigned.
Though the Census is taken for apportionment it is also important to help distribute billions of dollars annually in federal, state, local, and tribal funds. In addition the Census is used to draw state legislative districts, evaluate the success of programs, and identify populations in need of services.
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