The United States of America was founded on principles, which include a democratic form of government. , one of the most important principles outlined by founders of the country was freedom of religion. in the U.S. are free to practice the of their choice without fear of persecution. Religious was one of the main reasons many immigrants their countries to live in the United States. religious faiths have flourished within the United States. majority of Americans report that religion plays a important role in their lives, a proportion unique developed countries. Christianity is the most popular religion the country, but it is not the only practiced here by far.

During the country's infancy, , Roman Catholics, and mainline Protestants, as well as , arrived from Europe. Various Protestants, who left the of England, greatly diversified the religious landscape. Methodist Baptist churches increased drastically. Jehovah's Witnesses and the Day Saint movement spread also. Beginning in 1990s, religious share of Christians is decreasing due to , while Buddhism, Hinduism, Islam, and other religions are . Protestantism, historically dominant, ceased to be the religious of the majority in the early 2010s. What most important, however, is that all religions are to practice in the United States.

Christianity is the only religion to see a decline in in recent years. Nearly all religions are shrinking size because of the country's move to a secular way of life. Atheism is on the in the country as the number of people claim to be atheist or to have no connection is increasing.