270toWin.com has an interactive map of presidential elections.
American Ethnic Geography: Maps Related to Politics in the United States addresses issues of political regions, death penalty and executions and voter participation.
Atlapedia Online has political maps for most world countries.
Atlas of American Presidential Elections contains extensive data and maps of presidential elections.
ESRI Map Book Gallery has online copies of the ESRI collection of Map Books, which contain specially selected thematic maps submitted by people from many different disciplines.
Historical Atlas of the 20th Century has standing and interactive maps of the political, population, and government maps of the twentieth cnetury for countries all over the world, some of which are animated.
National Atlas has pre-formed maps as well as a Map Maker with hundreds of layers on different subject areas to make customizable maps of the U.S.
Perry-Castañeda Library Map Collection Historical Map Sites is the University of Texas' extensive list of links to historical map sites as well as individual maps, covering the U.S. and many world nations.