Catholic Church in the United States

With 23 percent of the United States' population as of 2018, the Catholic Church is the country's second-largest religious grouping after Protestantism, and the country's largest single church or Christian denomination where Protestantism is divided into separate denominations. In a 2020 Gallup poll, 25% of Americans said they were Catholic. The United States has the fourth-largest Catholic population in the world after Brazil, Mexico, and the Philippines.

Catholicism has had a significant cultural, social, and political impact on the United States, with the religion being long associated with the Democratic Party and left-wing political movements. Anti-Catholicism was the policy for the English who first settled the New England colonies, and it persisted in the face of warfare with the French in New France. The American Revolution and classical liberalism restored religious freedom for Catholics. The 1840s saw Catholics began to identify with the Democrats against the conservative and evangelical-influenced Whigs. This continued into the 20th century, where Catholics formed a core part of the New Deal Coalition. Since the 1970s, these ties have weakened, with Catholics often being regarded as swing voters. Two Catholics have been President of the United States: Democratic presidents John F. Kennedy (1961–1963) and Joe Biden (2021–present). While contradicting certain teachings of the church, surveys have repeatedly indicated that laity are more culturally liberal than the median voter, including on abortion rights and same-sex marriage.

Catholics are also the most likely of Christians in the United States to support the morality of casual sex. Institutional leadership tends to lean more traditionalist.