Australian Election Study (Australian National University)
British Election Study (University of Manchester, University of Oxford, & University of Nottingham) - Click "Explore our data" to get to data download.
Census.gov (Bureau of the Census, U.S. Dept. of Commerce)
Data.gov - "The home of the U.S. Government's open data"
Election Results (Federal Election Commission) -- "Every two years, the FEC publishes Federal Elections, a compilation of official, certified federal election results." and "The FEC also publishes a Combined Federal/State Disclosure and Election Directory. It provides contact information and links to the elections offices of the 50 states, the District of Columbia, American Samoa, Guam, Northern Mariana Islands, Puerto Rico and the U.S. Virgin Islands." Data starts with 1982, Excel download offered since 2000.
Foreign and International Government Statistical Agencies (Purdue University Libraries) - Not all countries offer the option to use their sites in English.
Gallup Poll information (until 2018; NexisUni database)
General Social Survey (GSS) from National Opinion Research Center, University of Chicago - Download in SPSS or STATA formats.
Immigration Data & Statistics (Homeland Security) includes the annual Yearbook of Immigration Statistics
NationMaster.com provides data from a variety of sources comparing countries
PARLINE database on national parliaments (Inter-Parliamentary Union) - Comparative data on parliaments, e.g., number of members, and results of parliamentary elections
Pew Research Center - Click "U.S. Politics" and then select Question Search. The Pew Center is a "nonpartisan fact tank" that "conducts public opinion polling, demographic research, media content analysis and other empirical social science research. Pew Research does not take policy positions."
Comparative Agendas Project (Dept. of Government, University of Texas at Austin) - This site maintains several data series.
Polling the Nations - Library subscription database containing poll questions and responses from more than 14,000 national, state, local and special public opinion polls and surveys conducted by 700 polling organizations in the United States and 80 other countries.
Roper Center (iPOLL public opinion database) - Library subscription database
Sourcebook of Criminal Justice Statistics (U.S. Bureau of Justice Statistics, online via University at Albany, SUNY)
Statista - Library subscription database
Statistical Abstract of the United States (2013- from ProQuest in print format only; 2012 & older from U.S. Census Bureau) - Print copies 1878-2012 in Andersen Library's 1st-floor Federal Documents collection. The online version from the Census lacks some tables containing copyrighted material. Starting with the 2013 edition, the government ceased producing this title.
Statistics, Data & Mapping/GIS Sources in State Agency (U.S.) (GODORT)
The Inter-university Consortium for Political and Social Research (ICSPR) at the University of Michigan in Ann Arbor is perhaps the largest online archive of social science data. UW-Whitewater is not a subscribing member, so you can usually view codebooks but not data, although it also links to some external data that may be openly accessible. Use the Google Scholar links to publications to determine whether UW-Whitewater provides access to the publications (to work off campus, configure your Google Scholar settings).