W. Virginia and Oregon, most non-believers per capita?
There's just a fascinating collection of mapped-outreligious demographics based on 2000 U.S. census data in an entry by Devilstower on Daily Kos. The one that caught my eye was "religious adherents as a percentage of all U.S. residents." It sure looks to me like West Virginia and Oregon have the lowest concentration, with North Dakota and Utah at a high "adherence" rate. Interesting that North Dakota has two fairly liberal senators in Byron Dorgan and Kent Conrad. Kind of blows the godless liberals argument out of the water, doesn't it?
But I encourage all to check out the maps showing where the Baptists, Mormons, Muslims, Jews, Catholics, and Amish, and Episcopals reside.
A special hat tip to the American Ethnic Geography course at Valparaiso university has the question covered. Geography remains a dominant and valuable discipline -- even if geographers can't really tell you what they do.*
*Disclosure: I graduated with a degree in Geography.
Update: Be sure to check out the comments by biscuits and Ann83 in the thread below.