ESRI, maker of ArcGIS mapping software, has chosen to use data from the Harvard Election Data Archive as the source for their maps of the 2012 electorate. John Rodden (Stanford), a contributor to the Archive, helped develop these electorate maps.
The Harvard Election Data Archive--sponsored by the Sloan Foundation, the Dean of the Faculty of Arts and Sciences at Harvard University, and the Institute for Quantitative Social Science-- contains data on election results, voting behavior, and electoral politics, with particular focus on the United States. The core data for the archive are state, county and district level election returns for all recent state and federal elections in the United States.
The goal of the Harvard Election Data Archive is to feed geo-referenced election data into newly-developed online redistricting software, which can be used as part of a more open, transparent redistricting process. The Harvard Election Data Archive archives and distributes its data using the IQSS Dataverse Network.