This handy 2-page guide by the Secular Policy Institute lists how religious each US state is, grouping them into secular liberal, secular conservative, moderate, and religious states. It also correlates states with which party they voted for in the 2014 US presidential election.
Data for this report was taken from Gallup’s Mississippi Most Religious State, Vermont Least Religious 2014 and Gallup’s Religion Remains a Strong Marker of Political Identity in U.S.