The United States has the world's largest Christian population.[414] In a 2014 survey, 70.6% of adults in the United States identified themselves as Christians;[415] Protestants in general accounted for 46.5%, while Catholics, at 20.8%, formed the largest single Christian denomination.[416] In 2014, 5.9% of the U.S. adult population claimed a non-Christian religion.[417] These include Judaism (1.9%), Islam (1.1%), Hinduism (0.7%), and Buddhism (0.7%).[417] The survey also reported that 22.8% of Americans described themselves as agnostic, atheist or simply having no religion—up from 8.2% in 1990.[416][418][419] Membership in a house of worship fell from 70% in 1999 to 47% in 2020, much of the decline related to the number of Americans expressing no religious preference. However, membership also fell among those who identified with a specific religious group.[420][421]
Protestantism is the largest Christian religious grouping in the United States, accounting for almost half of all Americans. Baptists collectively form the largest branch of Protestantism at 15.4%,[422] and the Southern Baptist Convention is the largest individual Protestant denomination at 5.3% of the U.S. population.[422] Apart from Baptists, other Protestant categories include nondenominational Protestants, Methodists, Pentecostals, unspecified Protestants, Lutherans, Presbyterians, Congregationalists, Episcopalians/Anglicans, Quakers, Adventists, Holiness, Christian fundamentalists, Anabaptists, Pietists, and multiple others.[422]