The Bible Belt is an informal region in the southeastern and south-central United States in which socially conservative evangelical Protestantism plays a strong role in society and politics, and Christian church attendance across the denominations is generally higher than the nation's average. The Bible Belt consists of much of the Southern United States as well as parts of adjacent areas. During the colonial period (1607–1776), the South was a stronghold of the Anglican church. Its transition to a stronghold of non-Anglican Protestantism occurred gradually over the next century as a series of religious revival movements, many associated with the Baptist denomination, gained great popularity in the region.
The region is usually contrasted with the mainline Protestantism and Catholicism of the Northeastern United States, the religiously diverse Midwest and Great Lakes, the Mormon Corridor in Utah and southern Idaho, and the relatively secular Western United States. Whereas the state with the highest percentage of residents identifying as non-religious is the New England state of Vermont at 34%, in the Bible Belt state of Alabama it is just 3%.Mississippi has the highest proportion of Baptists, at 75%. The earliest known usage of the term "Bible Belt" was by American journalist and social commentator H. L. Mencken, who in 1924 wrote in the Chicago Daily Tribune: "The old game, I suspect, is beginning to play out in the Bible Belt." Mencken claimed the term as his invention in 1927.
The name "Bible Belt" has been applied historically to the South and parts of the Midwest, but is more commonly identified with the South. In a 1961 study, Wilbur Zelinsky delineated the region as the area in which Protestant denominations, especially Southern Baptist, Methodist, and evangelical, are the predominant religious affiliation. The region thus defined included most of the Southern United States, including most of Texas and Oklahoma in the southwest, and in the states south of the Ohio River, and extending east to include central West Virginia and Virginia south of Northern Virginia. In addition, the Bible Belt covers most of Missouri and Kentucky and southern parts of Illinois, Indiana, and Ohio. On the other hand, areas in the South which are not considered part of the Bible Belt include heavily Catholic Southern Louisiana, central and southern Florida, which have been settled mainly by immigrants and Americans from elsewhere in the country, and overwhelmingly Hispanic South Texas. A 1978 study by Charles Heatwole identified the Bible Belt as the region dominated by 24 fundamentalist Protestant denominations, corresponding to essentially the same area mapped by Zelinsky.