Protestantism in the United States

Protestantism is the largest grouping of Christians in the United States, with its combined denominations comprising about 43% of the country's population (or 141 million people) in 2019. Other estimates suggest that 48.5% of the U.S. population (or 157 million people) is Protestant. This is the largest Protestant population of any country, around 20% of the world's total Protestant population. Baptists comprise about one-third of American Protestants. The Southern Baptist Convention is the largest single Protestant denomination in the U.S., comprising one-tenth of American Protestants. Twelve of the original Thirteen Colonies were Protestant, with only Maryland having a sizable Catholic population due to Lord Baltimore's religious tolerance.

The country's history is often traced back to the Pilgrim Fathers whose Brownist beliefs motivated their move from England to the New World. These English Dissenters, who also happened to be Puritans—and therefore Calvinists—were first to settle in what was to become the Plymouth Colony. America's Calvinist heritage is often underlined by various experts, researchers and authors, prompting some to declare that the United States was "founded on Calvinism", while also underlining its exceptional foundation as a Protestant majority nation. American Protestantism has been diverse from the very beginning with large numbers of early immigrants being Anglican, various Reformed, Lutheran, and Anabaptist.