A few weeks back I made the following map to show the religious population in each state, drawing on statistics from Pew Forum on Religion & Public Life. The data is from 2008.
A few things jump out at you: Evangelicals are concentrated in southern states; Catholics are found in the Northeast, North Central, and Southwest regions of the country; Mormons dominate Utah, and almost nowhere else. You’re most likely to find unaffiliated — people who claim no religion — in the far northeast or west of the Rockies. It is also surprising, in comparison to Christians, how few Jewish or Muslim people live in the U.S.