Originally set up to support Mock Convention research. We attempt to keep this page as up-to-date as possible.
The first two sources are very similar in structure and purpose -- they provide authoritative, non-partisan descriptions of political and socioeconomic conditions in each U.S. state and each Congressional district, as well as information on each member of Congress.
Biennially-published data collection.
Mostly campaign finance data, but also an Election Results section.
VCS is a private firm which builds and markets files of voter information for political campaigns and other users, although it is a little unclear how current the data is and why some jurisdictions are not included. Still, there is free survey data on voters in states, congressional districts, and counties.
Data on presidential, congressional, and gubernatorial elections.
State and regional overviews.
Congressional Quarterly. See especially Chapters 1 ("Elections and Political Parties") and 3 ("Public Opinion and Voting").
The Census Bureau is the premier data-gathering organization in the U.S. and it actually is the source of a lot of voting and registration data that shows up in other compilations.
The Voting and Registration section of the Census Bureau site includes several noteworthy collections, most notably the biennially-published Voting and Registration in the Election of November...which includes both a narrative report and detailed tables. Historical data also are availablein at least two categories: Population Characteristics Reports and Time Series Tables.
Another CQ publication.
The Elections and Politics section includes data on apportionment, turnout, voting, and more, including counts dating back to the late 18th century. Do not overlook the excellent overview essay.
The Electoral College, under the oversight of the National Archives, primarily is a repository of historical electoral data, although they also have valuable information on the 2008 election, including an Electoral College calculator.
"Since 1920, the Clerk of the House has collected and published the official vote counts for federal elections from the official sources among the various states and territories."
University of Richmond site provides "cinematic & interactive maps, and analysis, of the Presidential elections in the US from 1840-2004. This unique resource focuses on election data to the county level (rather than state)..."