"Data.gov starts an exciting new chapter in its evolution to make government data more accessible and usable than ever before."

Demographic and other statistics from the U.S. Census Bureau. Free U.S. Government Website.

Social Explorer is an online research tool designed to provide quick and easy access to historical census data and demographic information. It creates maps and reports to help users visually analyze and understand demography and social change throughout history. Users can customize, save, share, print, and email maps and reports and export them to a variety of programs and statistical packages for further analysis and use in reports and presentations.
For further information and tutorials, visit the Social Explorer Guide.

A comprehensive collection of statistics related to social, political and economic conditions in the United States. Published annually by the government since 1878; as of 2013 published by Proquest. Updated monthly.