Electoral college votes, 1789-present, general election popular vote counts by state, 1824-present; voter turnout by state, 1960-present, presidential primary results by state, 2000-2008, senatorial election results by state, 1990-present.
Contains several datasets of county- and state-level returns for all elections to the offices of president, governor, United States senator, and United States representative.
Select Politicians & Elections to search donors, find fundraising by candidate, outside spending, and personal finances, 2004-present. Select Influence & Lobbying for contributions by PACs, 527 organizations, and lobbyists, 1998-present.
Aggregating from state disclosure agencies, the National Institute on Money in State Politics provides access to campaign contribution data for candidates in state-level elections.
Contributions to and expenditures of political candidates, political action committees, ballot question committees, and political party committees in Maine.
These studies allow researchers to explore the relationship between demographics, socioeconomics, party affiliation, and electoral participation, among other variables. Available for download to SPSS or Stata, or for online analysis using SDA.
Data on reported voting and registration, method of voting, and reasons for not voting, by various demographic and socioeconomic characteristics at national level for election years, 1964-present.
Voter turnout and voting age population statistics, types of electoral systems and models of electoral management, and more in-depth information on national practices.
Archived data sets from national election studies around the world may be found in ICPSR, the largest data archive. Search for your country of interest and "election study." Most data sets available for download in SPSS, SAS, or Stata formats.
The Oxford Handbook of American Elections and Political Behavior
How to Research Elections by 
