Atlas of U.S. Presidential Elections (1789+) -- provides maps of election results for president, governors, and senators.
Election Statistics (1920+) -- "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." Provided as pdf files, the title varies:
Statistics of the presidential and congressional election of ... : showing the highest vote for presidential electors, and the vote cast for each nominee for United States senator, representative, resident commissioner, and delegate to the ... Congress, together with a recapitulation thereof, including the electoral vote
Politics1.com -- a non-partisan site providing links for the federal & state candidates, political parties, political news, and campaign issues.
Voting America: United States Politics, 1840-2008 (University of Richmond) -- "examines the evolution of presidential politics in the United States across the span of American history. The project offers a wide spectrum of cinematic and interactive visualizations of how Americans voted in presidential elections at the county level over the past 164 years. You can also find expert analysis and commentary videos that discuss some of the most interesting and significant trends in American political history."