Official government source for a broad range of social, demographic, business, and economic statistics. Historical data can be found under the "Publications" links on the Census homepage.

Allows for the creation of tables of basic demographic and economic statistics for countries of the world. Data available from 1950 to present.

Sponsored by the University of Minnesota, the NHGIS contains "summary statistics and GIS files for U.S. censuses and other nationwide surveys from 1790 through the present."

A subset of USA.gov, provides a list along with links of data producing federal and state agencies. Also includes links to government sites that provide data maps.