The religious history of the United States began with the first Pilgrim settlers who came on the Mayflower in the year 1620. Their Protestant faith motivated their movement as a community to the New World from Europe where they could practice in peace. The Spanish set up a famous network of Catholic missions in California, but they had all closed long before 1848 when California became part of the US. There were a few French Catholic churches and institutions in Louisiana, especially New Orleans.

Religious Diversity

Most of the settlers came from Protestant backgrounds in Britain and the Continent, with a small proportion of Catholics (chiefly in Maryland) and a few Jews in port cities. The English and the German Americans brought along multiple Protestant denominations. Several colonies had an "established" church, which meant that local tax money went to the established denomination. Freedom of religion became a basic American principle, and numerous new movements emerged, many of which became established denominations in their own right.

Historians debate how influential Christianity was in the era of the American Revolution. Many of the founding fathers were active in a local church; some of them, such as Jefferson, Franklin, and Washington had Deist sentiments. Experts, researchers and authors have referred to the United States as a "Protestant nation" or "founded on Protestant principles," specifically emphasizing its Calvinist heritage.

The First Great Awakening, the nation's first major religious revival in the middle of the 18th century injected new vigor into Christian faith. Religion in the period of the Second Great Awakening became increasingly involved in social reform movements, such as anti-slavery. Most of the denominations set up colleges to train new generations of leaders and nearly all were founded as Christian institutions. Later the Roman Catholics also set up colleges and a separate parochial school system to avoid the Protestant tone of the public schools.

Black Americans, once freed from slavery, were very active in forming their own churches, most of them Baptist or Methodist, and giving their ministers both moral and political leadership roles. In the late 19th and early 20th century most major denominations started overseas missionary activity. The "Mainline Protestant" denominations promoted the "Social Gospel" in the early 20th century, calling on Americans to reform their society; the demand for prohibition of liquor was especially strong. After 1970, the mainline denominations (such as Methodists, Presbyterians and Episcopalians) lost membership and influence. The more conservative evangelical, fundamentalist, and charismatic denominations (such as the Southern Baptists) grew rapidly until the 1990s and helped form the Religious Right in politics. The Catholic element grew steadily, especially from Hispanic immigration after 1970.

As Europe secularized in the late 20th century, the Americans largely resisted the trend, so that by the 21st century the US was one of the most strongly Christian of all major nations. Religiously based moral positions on issues such as abortion and homosexuality played a hotly debated role in American politics.

Religion in the United States is characterized by a diversity of religious beliefs and practices. Various religious faiths have flourished within the United States. A majority of Americans report that religion plays a very important role in their lives, a proportion unique among developed countries.

Historically, the United States has always been marked by religious pluralism and diversity, beginning with various native beliefs of the pre-colonial time. In colonial times, Anglicans, Catholics and mainline Protestants, as well as Jews, arrived from Europe. Eastern Orthodoxy has been present since the Russian colonization of Alaska. Various dissenting Protestants, who left the Church of England, greatly diversified the religious landscape. The Great Awakenings gave birth to multiple Evangelical Protestant denominations; membership in Methodist and Baptist churches increased drastically in the Second Great Awakening.

The majority of U.S. adults self-identify as Christians, while around 20-25% claim no religious affiliation. According to a 2017 study by the Public Religion Research Institute, approximately 69% of the Americans identified themselves as Christians, with 45% professing attendance at a variety of churches that could be considered Protestant, and 20% professing Catholic beliefs. The same study says that other non-Christian religions (including Judaism, Buddhism, Hinduism, and Islam) collectively make up about 7% of the population.

The United States federal government was the first national government to have no official state-endorsed religion. However, some states had established religions in some form until the 1830s.

Abrahamic religions

Christianity

The most popular religion in the U.S. is Christianity, comprising the majority of the population (69% of adults in 2017). According to the Association of Statisticians of American Religious Bodies newsletter published March 2017, based on data from 2010, Christians were the largest religious population in all 3,143 counties in the country. Roughly 46.5% of Americans are Protestants, 20.8% are Catholics, 1.6% are Mormons (the name commonly used to refer to members of The Church of Jesus Christ of Latter-day Saints), and 1.7% have affiliations with various other Christian denominations. Christianity was introduced during the period of European colonization.

According to a 2012 review by the National Council of Churches, the five largest denominations are:

· The Catholic Church, 68,202,492 members

· The Southern Baptist Convention, 16,136,044 members

· The United Methodist Church, 7,679,850 members

· The Church of Jesus Christ of Latter-day Saints, 6,157,238 members

· The Church of God in Christ, 5,499,875 members

Judaism

After Christianity, Judaism is the next largest religious affiliation in the US, though this identification is not necessarily indicative of religious beliefs or practices. There are between 5.3 and 6.6 million Jews. A significant number of people identify themselves as American Jews on ethnic and cultural grounds, rather than religious ones. For example, 19% of self-identified American Jews do not believe God exists. The 2001 ARIS study projected from its sample that there are about 5.3 million adults in the American Jewish population: 2.83 million adults (1.4% of the U.S. adult population) are estimated to be adherents of Judaism; 1.08 million are estimated to be adherents of no religion; and 1.36 million are estimated to be adherents of a religion other than Judaism. ARIS 2008 estimated about 2.68 million adults (1.2%) in the country identify Judaism as their faith. According to a 2017 study, Judaism is the religion of approximately 2% of the American population.

Touro Synagogue, (built 1759) in Newport, Rhode Island has the oldest still existing synagogue building in the United States.

Jews have been present in what is now the US since the 17th century, and specifically allowed since the British colonial Plantation Act 1740. The Jewish community in the United States is composed predominantly of Ashkenazi Jews whose ancestors emigrated from Central and Eastern Europe. There are, however, small numbers of older (and some recently arrived) communities of Sephardi Jews with roots tracing back to 15th century Iberia (Spain, Portugal, and North Africa). There are also Mizrahi Jews (from the Middle East, Caucasia and Central Asia), as well as much smaller numbers of Ethiopian Jews, Indian Jews, Kaifeng Jews and others from various smaller Jewish ethnic divisions. Approximately 25% of the Jewish American population lives in New York City.

According to the Association of Statisticians of American Religious Bodies newsletter published March, 2017, based on data from 2010, Jews were the largest minority religion in 231 counties out of the 3143 counties in the country. According to a 2014 survey conducted by the Pew Forum on Religion and Public life, 1.7% of adults in the U.S. identify Judaism as their religion. Among those surveyed, 44% said they were Reform Jews, 22% said they were Conservative Jews, and 14% said they were Orthodox Jews.According to the 1990 National Jewish Population Survey, 38% of Jews were affiliated with the Reform tradition, 35% were Conservative, 6% were Orthodox, 1% were Reconstructionists, 10% linked themselves to some other tradition, and 10% said they are "just Jewish".

Congregation Shearith Israel (founded 1655) in New York is the oldest Jewish congregation in the United States.

The Pew Research Center report on American Judaism released in October 2013 revealed that 22% of Jewish Americans say they have "no religion" and the majority of respondents do not see religion as the primary constituent of Jewish identity. 62% believe Jewish identity is based primarily in ancestry and culture, only 15% in religion. Among Jews who gave Judaism as their religion, 55% based Jewish identity on ancestry and culture, and 66% did not view belief in God as essential to Judaism.

A 2009 study estimated the Jewish population (including both those who define themselves as Jewish by religion and those who define themselves as Jewish in cultural or ethnic terms) to be between 6.0 and 6.4 million. According to a study done in 2000 there were an estimated 6.14 million Jewish people in the country, about 2% of the population.

According to the 2001 National Jewish Population Survey, 4.3 million American Jewish adults have some sort of strong connection to the Jewish community, whether religious or cultural. Jewishness is generally considered an ethnic identity as well as a religious one. Among the 4.3 million American Jews described as "strongly connected" to Judaism, over 80% have some sort of active engagement with Judaism, ranging from attendance at daily prayer services on one end of the spectrum to attending Passover Seders or lighting Hanukkah candles on the other. The survey also discovered that Jews in the Northeast and Midwest are generally more observant than Jews in the South or West. Reflecting a trend also observed among other religious groups, Jews in the Northwestern United States are typically the least observant of tradition.

The Jewish American community has higher household incomes than average, and is one of the best educated religious communities in the United States.

Islam

Islam is the third largest religion in number in the United States, after Christianity and Judaism, representing approximately 1% of the population in 2017. According to the Association of Statisticians of American Religious Bodies newsletter published in March 2017, based on data from 2010, Muslims were the largest minority religion in 392 counties out of the 3143 counties in the country. Islam in America effectively began with the arrival of African slaves. It is estimated that about 10% of African slaves transported to the United States were Muslim. Most, however, became Christians, and the United States did not have a significant Muslim population until the arrival of immigrants from Arab and East Asian Muslim areas. According to some experts, Islam later gained a higher profile through the Nation of Islam, a religious group that appealed to black Americans after the 1940s; its prominent converts included Malcolm X and Muhammad Ali. The first Muslim elected in Congress was Keith Ellison in 2006, followed by André Carson in 2008.

The Islamic Center of America in Dearborn, Michigan, is the largest mosque in the United States.

Research indicates that Muslims in the United States are generally more assimilated and prosperous than their counterparts in Europe.

Dharmic religions

Buddhism

Buddhism entered the US during the 19th century with the arrival of the first immigrants from East Asia. The first Buddhist temple was established in San Francisco in 1853 by Chinese Americans.

During the late 19th century Buddhist missionaries from Japan came to the US. During the same time period, US intellectuals started to take interest in Buddhism.

According to a 2017 study, Buddhists are approximately 1% of the American population.

Hinduism

Detail of Malibu Hindu Temple in Calabasas, California

Hinduism is the fourth largest faith in the United States, representing approximately 1% of the population in 2017. The first time Hinduism entered the U.S. is not clearly identifiable. However, large groups of Hindus have immigrated from India and other Asian countries since the enactment of the Immigration and Nationality Act of 1965. During the 1960s and 1970s Hinduism exercised fascination contributing to the development of New Age thought. During the same decades the International Society for Krishna Consciousness (a Vaishnavite Hindu reform organization) was founded in the US.

In 2001, there were an estimated 766,000 Hindus in the US, about 0.2% of the total population.[85][86] According to the Association of Statisticians of American Religious Bodies newsletter published March, 2017, based on data from 2010, Hindus were the largest minority religion in 92 counties out of the 3143 counties in the country.[24]

In 2004 the Hindu American Foundation—a national institution protecting rights of the Hindu community of U.S.—was founded.

American Hindus have one of the highest rates of educational attainment and household income among all religious communities, and tend to have lower divorce rates.[53]

East Asian religions

Taoism

In 2004 there were an estimated 56,000 Taoists in the US.[93] Taoism was popularized throughout the world through the writings and teachings of Lao Tzu and other Taoists as well as the practice of Qigong, Tai Chi Chuan and other Chinese martial arts.

No religion

In 2017, approximately 24% of the Americans declared to be not religiously affiliated.