ICPSR provides a wealth of data on numerous social science topics. Data can be downloaded into many statistical packages (R, Stata, SPSS, etc). You need to create a user/name and password using your berkeley.edu email address to download the data. Below are some of their election data sources.
Names of candidates, political party name and ICPSR party ID code, and the number of votes received by each candidate in elections between 1788 and 1990. UCB ONLY
Contains district level election data for 1961-65, data for the House of Representatives elections from 1952-1962, and presidential elections from 1952-1960. Also provides population and housing characteristics for each district.
Provides easy access to a wide variety of economic, social, political, and marketing indicators. (DataPlanet - Data-Planet - Statistical Datasets)
Offers easy access to over 5,550 data sets from over 65 source providers and 16 subject categories, including banking, criminal justice, education,energy, food and agriculture, government, health, housing and construction,industry and commerce, labor and employment, natural resources and environment, income, cost of living, stocks, transportation, and more. Sources of data include federal, local, state and international governments and organizations. Allows for customization of the data by selecting subjects, and the ability to view your data in side-by-side tables, charts and maps.
Data and interactive thematic maps from the U.S. Census from 1790-present.
Provides access to current and historical United States census data, including all historic decennial censuses and American Community Surveys, as well as other demographic information, such as religious organizations. Census data is current to 2010 and historical back to 1790. In addition to being a data resource, the web interface lets users create maps and reports to better illustrate, analyze and understand demography and social change.
Offers a wide spectrum of animated and interactive visualizations of how Americans voted in elections over the past years. You can also find expert analysis and commentary videos that discuss some of the most interesting and significant trends in American political history.
Provides cinematic and interactive maps, and analysis, of the Presidential elections in the US from 1840-2004. Focuses on election data to the county level (rather than state). Allows users to compare elections as well as recognize the significance of individual elections by geographic region, political party, voter turnout, voter demographics, and more.