Short answers, pulled from the story.
American journalist and social commentator H. L. Mencken coined the term Bible Belt. He first used it in the Chicago Daily Tribune in 1924, writing that "the old game, I suspect, is beginning to play out in the Bible Belt." In 1927, Mencken claimed the term as his own invention.
The Bible Belt encompasses the Deep South states of South Carolina, Georgia, Alabama, Mississippi, and most of Louisiana; the Upland South states of North Carolina, Tennessee, Kentucky, Arkansas, and Oklahoma; and the southern Mid-Atlantic states of Virginia and West Virginia. It also includes most of Texas, North Florida, southern Missouri, and parts of southern Indiana and southern Ohio.
Arkansas has the highest proportion of evangelical Protestants of any state, at 50 percent. A 2016 Pew Research Center study found the ten most religious states were Alabama, Mississippi, Tennessee, Louisiana, Arkansas, South Carolina, West Virginia, Georgia, Oklahoma, and North Carolina.
Several cities claim the title. Nashville, Tennessee, sometimes called "the Protestant Vatican," hosts over 700 churches, the headquarters of the Southern Baptist Convention, and Thomas Nelson, described as the world's largest producer of Bibles. Charlotte, North Carolina, the birthplace of Billy Graham, and Tulsa, Oklahoma, are also strong contenders. An American Bible Society study of 42,855 interviews named Knoxville, Tennessee, the most Bible-minded city in the country.
The Philadelphia Baptist Association, founded in 1707, drove early missionary expansion southward. The key figure was Shubal Stearns, a New England Separate Baptist who migrated to Sandy Creek, North Carolina, in 1755 and sparked a revival across the Piedmont. His churches were organized into the Sandy Creek Association in 1758, and his brother-in-law Daniel Marshall became the first great Baptist leader in Georgia, founding Kiokee Baptist Church, the oldest continuing Baptist congregation in the state.
Alabama, Mississippi, South Carolina, and Texas have voted Republican in every presidential election since 1980. Oklahoma has backed the Republican candidate since 1968, with Republicans carrying every county in the state in every presidential election since 2004. Kentucky, Louisiana, West Virginia, Arkansas, Missouri, and Tennessee have voted Republican in every election since 1996.
Yes. The Netherlands has the Bijbelgordel, stretching from Zeeland through the Veluwe to Overijssel. Denmark's Bible Belt covers rural western Jutland, centered on conservative Lutheran communities. In Sweden it is focused on Jonkoping. Mexico has a parallel concept called the Rosario Belt, named by journalist Carlos Monsivas in 1999, covering states where 90 percent of the population is Roman Catholic. Before independence, Soviet Ukraine was described as the Bible Belt of the Soviet Union.