General election results and maps for presidential elections from 1789 to the present, as well as presidential primary results from 1992 to the present. In addition, Dave Leip's Atlas sells election data sets, including the 2016 general election results by congressional district and the presidential election results by county from 1912 to the present.
Every two years, the FEC publishes Federal Elections, a compilation of official, certified federal election results. These publications include primary, runoff and general election results for the Senate, the House of Representatives and when applicable the President.
A searchable collection of election returns from 1787 to 1825. The data were compiled by Philip Lampi. The American Antiquarian Society and Tufts University Digital Collections and Archives have mounted it online with funding from the National Endowment for the Humanities. The site contains federal and state election returns, including presidential elections.