Business Insider has on its site a map showing the county by county break of religion affiliation in America. The site reports:
A few observations from the perspective of 2013:
The Church of Jesus Christ of Latter-day Saints, aka the Mormon Church, seems to have heeded Mark Twain's advice: "Buy land, they're not making it anymore." In November the Mormon Church bought 2% of Florida.
The Bible Belt, comprised mostly of Southern Baptists, is on full display and informs the strong social conservative strain that runs through American politics.
Catholics barely beat out the Southern Baptists for the highest number of counties with the most adherents. Catholicism's nationwide reach is reminiscent of widespread support of the Notre Dame football team:
"Millions of Catholics—whether Irish, Italian, German or Pole —lived vicariously through the wins and losses of Notre Dame’s football teams. For that vastly immigrant population Notre Dame football symbolized the triumphs of an ostracized people. It also reflected the ascendancy of U.S. Catholics into the nation’s mainstream."
Kansas, Illinois, Indiana, and West Virgina appear to have the most diversity when it comes to dominant religious groups. On the other side is Vermont and New Hampshire, which are considered the Godless states.
Click on map to make it larger...