Gallup has ranked the states from most to least religious, and I live in the 4th most religious of the states. This is how they judged:
For the current ranking, Gallup uses the responses to a straightforward question that asks: "Is religion an important part of your daily life?" The rankings are based on the percentage of each state's adult (18 and older) population that answers in the affirmative.
The picture above came from the Gallup site and clearly shows that solid Southern Bible belt.
I saw it somewhere else first but can't find that now so I'm giving my hat tip to John Meunier.
Dispatches from the Culture Wars digs deeper and finds that Tennessee may be the 4th most religious state but it's 3rd in out-of-wedlock births and 4th highest in teen pregnancies. Way to go, Tennessee. Show'em how to walk that walk! Here's proof that feeling "religious" doesn't lead to living "religious".