The Pew Forum on Religion & Public Life survey of the American Religious Landscape is more than three years old and, because of its size and cost, won't be updated for another two years, but it remains an important reference source and worth taking a look at.
Pew Forum interviewed 35,556 American adults to compile this detailed profile, and the result is displayed in an interactive graphic published by USA Today.
Move the cursor over each state and it you will see a detailed breakdown of religious affiliations. Numbers are for those who identify themselves with a particular religion; nationally, 16% said they are unaffiliated.
The largest group in the country is Evangelical Protestants (26%), followed by Catholics (24%) and Mainline Protestants (18%). Jews are 2%, Moslems and Buddhists 1% each.
New York is 39% Catholic, 11% Evangelical and 6% Jewish.
Those with the largest Jewish population are what you'd expect: New Jersey (6%), Maryland and the District of Columbia (5% each), Massachusetts and Florida (3% each) and several more at 2%.
In Utah, where Jews account for less than half of one percent, Mormons are 58% of the population.
Nevada has the largest Muslim population (2%, vs. 1% Jews).
In Oregon, Buddhists outnumber Jews, Muslims and Hindus combined.
The study, compiled in 2007 and released in June 2008, is the latest data available. "Since it is an enormous undertaking to interview 35,000+ Americans (and costly)," a Pew Forum official told me, it cannot be updated every year. The organization hopes to conduct its next U.S. Religious Landscape Survey in 2013. Until then, this is the best data available and the one most relied upon by the media and others. It is interesting, instructive and you can examine it in detail here.