Demography

• Census data 1790-1960
• Census Bureau
• Population Index
• Bureau of Labor Statistics
• U.S. Citizenship and Immigration Services
• Pew Hispanic Center

Religion

• Pew Forum on Religion and Public Life
• Association of Religion Data Archives
• Adherents.com (religious data)
• American Religious Identification Survey
• Pluralism Project
• Religion and the Founding (Lib. of Cong.)

• Pollster.com
• The Polling Report
• RealClearPolitics
• People Press & Politics (Pew Trust)
• Annenberg National Election Survey
• Vanishing Voter Project
• National Election Studies/ICPSR
• MediaCurves
• Center on Policy Attitudes
• Quinnipiac University Polling Institute
• Roper Center
• Gallup Poll
• Public Opinion Strategies
• Los Angeles Times polls
• Washington Post polls
• Public Agenda

• Presidential election exit polls through 1996 (NY Times)
• Congressional election exit polls through 1998 (NY Times)
• State-level results and exit polls 1998
• Exit polls 2000 (CNN)
• Exit polls 2004 (CNN)
• Exit polls 2006 (CNN)
• Old CNN/USA Today/Gallup polls
• Americans & the World (opinion on international relations)
• WorldPublicOpnion.org
• Pew Global Attitudes Project
• Zogby International
• "Pollkatz" Presidential Approval
• Health Poll Search (Kaiser Foundation)
• American Association for Public Opinion Research