Watch 112 years of American elections take place in two minutes below:

County Maps courtesy of Minnesota Population Center.
National Historical Geographic Information System: Version 2.0.
Minneapolis, MN: University of Minnesota 2011
www.nhgis.org

Combined election data from:

WD Burnham: Presidential Ballots, 1836-1892 – EE Robinson: The Presidential Vote: 1896 to 1932 – RM Scammon: America at the Polls (1920-1964) – RM Scammon: America at the Polls (1968-1984 ) – RM Scammon / A. McGillivray: America Votes No. 18, 1988 , No. 20, 1992 , No. 22, 1996 , No. 24, 2000,  Election results by county and figures Bureau of the Census for 1880, 1920, 1960 and 2000

Generously mapped by geoelections.free.fr
Map referencing by presidency.ucsb.edu & fec.gov/general/library.shtml