http://www.nytimes.com/interactive/2014/10/03/upshot/ncaa-football-map.html#4,46.272,-104.340
BYU has healthy percentages in the whole state, but Utah appears to dominate. It's also been interesting to live in Arkansas where there is no in-state rivalry. Everyone cheers for the Hogs - no matter how bad they are. Nebraska looks even more solid.
I also thought it's interesting how the most popular team in Maine and New Hampshire is Florida. Granted, they only have 8%, but it seems really random.