The chart above shows the most and least religious states in the United States. It is from a Gallup Poll -- done between January 2nd and December 30th of 2016 of a random national sample of 174,969 adults, and has a margin of error of less than 1 point. The margin of error for the individual states is between 3 points and 6 points, depending on the size of the state's sample.
The most religious state is Mississippi, where 59% said they were very religious and only 12% said they were not religious. Finishing close behind were Alabama (56% to 16%) and Utah (54% to 30%). Eight states had at least 50% of respondents saying they were very religious.
The least religious states were Vermont (21% to 58%), Maine (23% to 50%), and Massachusetts (25% to 48%). Three states had at least 50% saying they were not religious at all (Vermont, Maine, and New Hampshire).
For the United States as a whole, 38% said they were very religious and 32% said they were not religious at all.