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U.S. Census: Home

From Off Campus

Most Library online resources can be accessed from off campus by current UD faculty, staff, and students. When using links on these pages, you may be prompted for your UDelNetID and password. Please report any issues you encounter while accessing Library databases, e-journals, or e-books.

Small Geographic Areas

  • The smallest geographic areas that the Census Bureau collects data for are: Census Tracts, Block Groups, and Blocks. These areas are only covered in the decennial censuses. The Census Bureau and the Department of Agriculture also collect data at the ZIP Code level.
  • Census Tracts and Block Numbering Areas (Census Bureau)
  • ZIP Code Statistics (Census Bureau)


The Decennial Census

The federal census has been taken every 10 years (decennially) since 1790. The taking of the census is established in Article 1, Section 2 of the United States Constitution.

Census Geography

The Census Bureau reports data for a wide variety of geographic types, ranging from the entire United States down to a Census Block. Some geographic types follow recognized boundaries, such as counties and cities. Others are created by the Census Bureau.

Geography: Reference (Census Bureau)

The diagram shows the many geographic types for which data are available. In general, larger geographic types (e.g., state) are shown near the top and smaller geographic types (e.g., census tract) are shown towards the bottom.


Census Geography: "Help" in American FactFinder.

Featured Database: Statistical Abstract of the United States (ProQuest)

Statistical Abstract has long been the authoritative resource for statistics. This is the single most important source for starting a statistical search. Statistical Abstract collects data for all facets of social, economic, and political life and includes all federal sources, some commercial publishers, and some professional and trade organizations. Tables have notes about sources of the data which can lead to other statistics. Tables are available in .pdf and Excel (.xls) formats.

Beginning with the 2013 edition, it is available in database format.

Statistical Abstract of the United States (Online Edition) (ProQuest)

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Important Information about HIstorical Census Statistics

This book examines census information, such as instructions to enumerators. These instructions led to undercounting women and misrepresenting women's occupational status.