Sections of the South, Southwest and southern Midwest in the United States make up what is known as the Bible Belt, because they have traditionally been populated with a high number of evangelical Protestants, particularly Baptists, and are associated with a socially conservative culture based on biblical religious beliefs. Like the rest of the country in general, the Bible Belt has witnessed a steady and often dramatic decline in religious influence and church participation in recent decades. However, Christian organizations still wield an enormous amount of political and social clout.

General National Decline

Recent polls, including ones by Gallup, Pew and the Public Broadcasting Service, show a steady decrease in religious belief, church attendance and confidence in organized religion across the United States, specifically among young Americans. An estimated 20 percent of Americans are now atheist or agnostic, or claim no religious affiliation, making non-believers and the religiously unaffiliated a larger percentage of the population than members of any denomination in the U.S. except Catholics and Baptists -- and the fastest growing. As much as a third of people younger than 30 are atheist, agnostic or claim no religious affiliation. The number of nonbelievers has more than doubled since the 1970s, a decade that saw a sharp decline from polling done in the 1950s.

General Protestant Decline

It is estimated that the percentage of Americans who identify as Christian has dropped to 76 percent from 86.2 percent since 1990. Of that decline, a full 90 percent was among Protestant sects. Although a large portion of that decline is because of population loss in mainline denominations like the Episcopalian Church -- which isn't traditionally associated with large Southern numbers -- the general Protestant retreat has hammered the predominantly Protestant South, in both its mainline and evangelical communities.

Changing Demographics

Although the South is still disproportionately religious compared with the larger U.S. population, every Southern state saw a decline in its non-Catholic Christian population since 1990 except Louisiana, with nine of 15 states witnessing double-digit drops in percentages. The majority of immigrants are Latin American or Asian Catholics, who statistically have larger families than the median population. Experts point to this as a reason why adherence to Catholicism has not waned as drastically in the U.S.

Gender and Education

Southerners, like the country's population in general, go to college in much higher percentages than they did two generations ago. The largest group of people who rarely or never attend church are college students, with polls showing students to be more likely to never return to church after graduation. Women account for by far the largest percentage increase in college graduates since the 1960s. As a result, females who were once anchoring their churches are now going to college, where their membership is likely to wane.