Someone just sent me this:
http://www.valpo.edu/geomet/pics/geo.../adherents.gif
What struck me immediate wasn't where the high concentrations of faith are but where they aren't. Obviously, Salt Lake City and Orange County, CA are going to be large populations of the faithful, along with largely rural areas.
No, the surprising thing for me was places like West Virginia, Maine, Central Michigan (LP) and the band that runs through East Central Virginia through Eastern North Carolina. A lot of places can be explained by the predominant industry (universities in the case of Central Florida, gambling in Clark Co., NV) or the predominance of a particular brand of religion (Catholicism in Chicago), but why is Northern California so devoid of the faithful?
I put this in Politics because of the obvious ramifications this has with elections. If someone has the last general election results by county in this kind of format easily available to them, I think it would make an interesting comparision.