VotingAmerica allows you to see on maps (down to county level) how Americans have voted since 1840. There is much to this site that I haven’t mastered, but it seems very good and useful, and fun. Take a look. Note: Some of it seems to load slower than what has become normal. I recommend that when you start looking at the maps ("This application is processor- and memory-intensive.") you not try to do anything else on the web. I think it’s worth the wait.