Gerrymander data- http://clerkweb.house.gov/histrecs/history/elections/political/divisions.htm U.S. Congress- Partisan composition, 1855-2001 --- http://clerkweb.house.gov/histrecs/history/elections/elections.htm U.S. Congress and President elections data, 1920-1998 --- http://www.ncsl.org/programs/legman/elect/elredist.htm State legislatures minority rule gerrymander systems. The Partisan Composition link has current gerrymander results.