In a comment to a previous post, dreikin pointed out Valparaiso University’s collection of maps of religious affiliation in the U.S. This one shows overall religious adherence:
Most common Christian denominations by county:
The counties with a dot indicate that 50% or more of residents belong to the dominant denomination. Unsurprisingly, we see that the South is dominated by Baptists (which includes Southern Baptists). The relatively high prevalence of Lutherans in the upper Midwest is due to the large number of Scandinavian Lutherans who settled in that region in the late 1800s and early 1900s.
Below are breakdowns of some specific affiliations as a percentage of the total population. Be sure to check the legend on each map–the percents represented by the different colors vary greatly from map to map, which is sort of annoying. There are lots of other maps at the Valparaiso website, I just found these four interesting:
Amish (which I think are a subset of Mennonites, and so are technically part of the numbers reported in the map above):
NEW! Matt merged the religious adherents map (the first one in this post) with a map from a previous post about concentration of poverty:
Due to the coloring of the background map, this means that darkness of the blue areas correlates poverty with % religious adherents.