Since the advent of imperialism in what is now the United States of America, Christianity has been the country’s primary religion. According to Pew Research data, around 70.6% of Americans were Christian in 2014 (“Religious Landscape Study.” Pew Research Center). As of 2021, that number had dropped to 63%, while the number of religiously unaffiliated individuals had risen significantly (“How U.S. Religious Composition Has Changed in Recent Decades.” Pew Research Center). While there are many denominations of Christianity in America, Evangelical Protestantism is the most popular, accounting for a quarter of the nation’s population in 2014. Since the late 1800s, some Christians have begun to follow doctrines of Christian fundamentalism. Most fundamentalist denominations are Protestant Evangelical denominations; to be more specific, most fundamentalist Christians in America are Baptists. 

Over the course of the 20th century, Christian fundamentalism grew in popularity. It was primarily a reactionary movement prompted by cultural changes and new scientific ideas. In the early 20th century, some Christian groups began heavily promoting biblical literalism in opposition to Charles Darwin’s theory of evolution by natural selection. Fundamentalists looked to the Bible to promote a doctrine of young-Earth creationism that states that the Earth is only 6,000 years old and that it was created in seven 24-hour days.