Government Information Guide: Census & Statistics

Data.census.gov is the new platform to access data and digital content from the U.S. Census Bureau. The vision for data dissemination through data.census.gov is to improve the customer experience by making data available from one centralized place so that data users spend less time searching for data content and more time using it.
https://data.census.gov/cedsci/

Social, demographic, and economic data about the U.S. population.
https://www.census.gov

The most comprehensive source of information about individual counties and cities, with data for all U.S. states, counties, and cities with a population of 25,000 or more. It contains additional data for places with a population of 100,000 or more. Also included is a complete set of state maps showing all counties, places of 25,000 or more population, and metropolitan areas. 2007 is the most recent year available.
http://www.census.gov/statab/www/ccdb.html

The purpose of Data.gov is to increase public access to high value, machine readable datasets generated by the Executive Branch of the Federal Government

This annotated list from the University of Michigan Documents Center includes categories for demographics, sociology, and health, among others.
http://www.lib.umich.edu/libhome/Documents.center/stats.html

Choose from a variety of city, county and state statistical compilations.
http://www.firstgov.gov/Government/State_Local/Statistics.shtml

Global and internationally comparable statistics on education, science, technology, culture and communication.
http://www.uis.unesco.org/ev_en.php?ID=2867_201&ID2=DO_TOPIC

Annual compilation of U.S. crime statistics from the FBI. See also Crime in the United States.

International statistics on a wide range of social and economic topics from the United Nations.
https://unstats.un.org/unsd/

Files include data published for 2009 estimates and many items from the 2000 Census of Population and Housing, the 1990 census, the 1980 census and the 2002, 1997, 1992, 1987, 1982 and 1977 economic censuses. General topics : age, ancestry, banking, building permits, business patterns, crime, earnings, education, elections, employment, government, health, households, housing, income, labor force, manufactures, population, poverty, retail/wholesale trade, vital statistics and more.