Religious affiliation in the US.
This graph shows that about half of the country isn't protestant and that 'No religion'  is the third biggest group.

This map shows us where the different religions are most prominent, and which is the most common religion in a certain area. It goes by state and county.

The percentage of people by state in the United States who identify with a religion as opposed to having "no religion" (2001).
http://en.wikipedia.org/wiki/File:Religious_Belief_in_USA-states.png