Around 62% of Americans identify as Christian — roughly 40% Protestant and 19% Catholic — while about 28% now say they have no religion at all. That last group has roughly doubled since 2007 and is the single biggest change in American religious life in living memory. The United States remains far more religious than comparable wealthy democracies, and is becoming less so faster than any of them.
The Fastest-Growing Group Is No Religion
The religiously unaffiliated — atheists, agnostics and the much larger category answering "nothing in particular" — have gone from about 16% of adults in 2007 to roughly 28% today. Pew's most recent landscape study suggests the rise has levelled off in the last few years rather than continuing to climb, which is itself notable.
The group is younger and skews male: roughly four in ten adults under 30 are unaffiliated, against around one in six of those over 65. Most are not atheists. "Nothing in particular" is by far the largest sub-category, and a substantial share of it still believes in God and prays — they have dropped the institution rather than the belief.
This matters for interpreting every other figure here. American Christianity is not collapsing into unbelief; it is losing its institutional monopoly while retaining a great deal of diffuse religiosity.
Protestant Is Not One Thing
The 40% Protestant figure conceals the most fragmented religious landscape in the developed world. There is no Church of America. Surveys typically split the category three ways: evangelical Protestants, mainline Protestants, and the historically Black Protestant tradition.
Evangelicals are the largest and include Southern Baptists, Pentecostals, non-denominational churches and much else. The mainline — Methodists, Presbyterians, Episcopalians, Lutherans, the United Church of Christ — were culturally dominant into the mid-twentieth century and have declined sharply since. The Black church tradition, shaped by segregation and central to the civil rights movement, remains distinct in both worship and politics.
Non-denominational Christianity is the growth story. Congregations belonging to no denomination at all now account for a large and rising share of Protestant attendance, which makes the historical denominational categories progressively less useful for describing what Americans actually attend.
The First Amendment Cuts Both Ways
The United States was the first country to constitutionally separate church and state, and it did so in a single sentence. The First Amendment, ratified in 1791, bars Congress from making any law "respecting an establishment of religion, or prohibiting the free exercise thereof".
Article VI had already banned religious tests for public office. Several states nonetheless maintained established churches for decades afterwards — Massachusetts did not disestablish until 1833 — because the amendment originally bound only the federal government.
The two clauses pull against each other, and most American religious-liberty litigation is about where the line between them falls. Engel v. Vitale in 1962 struck down official prayer in public schools on establishment grounds. Employment Division v. Smith in 1990 narrowed free-exercise protection, prompting Congress to pass the Religious Freedom Restoration Act in 1993 almost unanimously — a statute that has since become one of the most contested in American law.
Why America Is Religious and Europe Is Not
The standard explanation is the separation itself. Because no denomination was ever established, none became identified with an unpopular state, and all had to compete for members. Sociologists describe the result as a religious marketplace: an unusually entrepreneurial ecosystem of congregations that must attract and retain people rather than assume them.
The pattern of American revivalism supports it. The First Great Awakening in the 1730s and 1740s and the Second from about 1790 to 1840 were mass movements led by itinerant preachers outside established hierarchies, and they permanently shifted the country's religious centre of gravity toward Baptists and Methodists.
Immigration reinforced it. Successive waves — Irish and Italian Catholics, German and Scandinavian Lutherans, Eastern European Jews, more recently Latin American Catholics and Pentecostals, South Asian Hindus and Muslims — each arrived with institutions that served as community infrastructure as much as places of worship.
Catholicism Arrived With Immigration and Stayed
Catholics are about 19% of adults and form the largest single religious body in the country, since Protestantism is split across thousands of denominations. Catholicism was a minority faith facing organised hostility for much of the nineteenth century — the Know Nothing movement of the 1850s was explicitly anti-Catholic — and John F. Kennedy's Catholicism was a live issue in the 1960 election.
The share has been remarkably stable for decades, but the stability is deceptive. Large numbers of white Catholics have left, offset almost exactly by Hispanic immigration; a majority of American Catholics under 30 are now Hispanic. The Church operates the largest private school system in the country and a hospital network treating a sixth of all US patients.
Utah and the Only Major Religion Founded in America
The Church of Jesus Christ of Latter-day Saints was founded by Joseph Smith in upstate New York in 1830 and is the only world religion of any scale to originate in the United States. Persecution drove its members west, and Brigham Young led them to the Salt Lake valley in 1847.
The result is the most religiously distinctive state in the union. Utah is somewhere around 55 to 60% Latter-day Saint, and the concentration shapes state law on alcohol, the structure of civil society and the highest birth rate in the country. Membership worldwide now exceeds 17 million, with more members outside the United States than inside.
The Bible Belt Is Measurable
Regional variation in the United States is wide enough that national averages describe almost nobody. Mississippi and Alabama report daily prayer and weekly attendance at roughly double the rates of Massachusetts, New Hampshire and Vermont.
The Bible Belt across the South and parts of the Midwest is heavily evangelical Protestant. The Northeast is Catholic and, increasingly, unaffiliated. The Pacific Northwest has been called the "None Zone" since long before the national rise of the unaffiliated. Utah and southern Idaho are Latter-day Saint.
These are not small gaps. On most measures of religiosity the distance between Mississippi and Vermont is comparable to the distance between two different countries.
Judaism, Islam and the Growing Minorities
American Jews number around 2% of the population, roughly 7.5 million people, the second-largest Jewish community in the world after Israel's. They are concentrated in New York, Florida, California and New Jersey, and are divided between Orthodox, Conservative, Reform and unaffiliated streams, with the Orthodox share rising because of much higher birth rates.
Muslims and Hindus are each around 1%, both growing through immigration and both notably young. American Muslims are unusually diverse by origin — South Asian, Arab, African and a substantial African American population with its own history through the Nation of Islam and mainstream Sunni conversion. Buddhists are around 1%, split between Asian American communities and converts.
Megachurches and the American Congregation
The United States has something in the order of 350,000 congregations, and their size distribution is extreme. Most are small — the median congregation has under 100 regular attendees — while a small number are enormous.
Roughly 1,700 Protestant churches qualify as megachurches with 2,000 or more weekly attendees. Lakewood Church in Houston, meeting in a former basketball arena, is the largest at over 40,000. These institutions run bookstores, cafés, schools, counselling services and broadcast operations, and function as social infrastructure well beyond Sunday.
The model is also an export. American-founded Pentecostal and charismatic movements have grown far faster abroad than at home, particularly in Latin America and sub-Saharan Africa.
Religion and Politics Are Unusually Fused
Nowhere else in the developed world does religious affiliation predict voting behaviour as strongly. White evangelical Protestants have voted Republican by margins around four to one in recent presidential elections; the religiously unaffiliated and Black Protestants lean heavily Democratic; Catholics split roughly down the middle and are treated as a swing bloc.
The alignment is recent. Evangelicals were not a reliable partisan bloc before the late 1970s, and the shift is usually traced to the mobilisation around Roe v. Wade, federal action on segregated religious schools, and organisations such as the Moral Majority founded in 1979.
There is also a feedback effect running the other way. Political scientists have argued that part of the rise in the unaffiliated is a reaction to that fusion — Americans who dislike the politics distancing themselves from the religious label attached to it, rather than from belief itself.
Where the Trend Points
Every long-running measure of American religiosity is down: membership, attendance, prayer frequency, belief in God with absolute certainty. Church membership fell below 50% of adults for the first time in Gallup's polling in 2020, having been around 70% at the end of the 1990s.
But the decline is uneven and slowing. Generational replacement is the main mechanism rather than adults changing their minds, and the youngest cohorts have not been getting steadily less religious than the ones immediately before them. Projections that show American Christianity falling below half the population by mid-century depend heavily on whether the recent plateau holds.
The trajectory also runs the other way from most of the rich world, including Canada, whose numbers looked like America's in 1970 and now look European. What is not in doubt is the direction relative to the past: the United States is still an outlier among rich countries for how religious it is, and it is a smaller outlier every decade. Set against France's strict secularism or Germany's church tax, the American arrangement — no establishment, no funding, and far more churchgoing — remains the odd one out.