A state religion (also called an established church or state church) is a religious body or creed officially endorsed by the state. The term state church is most closely associated with Christianity, although it is sometimes used in the context of other faiths as well. Closely related to state churches are what sociologists call ecclesiae, though the two are slightly different.
Types of state churches
The degree of state endorsement of a state religion varies, from mere endorsement and financial support, with freedom for other faiths to practice, to prohibiting any competing church from operating and persecuting the followers of other churches. In Europe, competition between Catholic and Protestant denominations for state sponsorship in the 16th century evolved the principle cuius regio eius religio embodied in the text of the treaty that marked the Peace of Augsburg, 1555.
In some communist countries, notably the People's Republic of China, the state sponsors religious organizations, and activities outside the state-sponsored religious organizations are met with various degrees of official disapproval. In these cases, state religions are widely seen as efforts by the state to prevent alternate sources of authority.
Sociology of state churches
Sociologists refer to mainstream non-state religions as denominations. State religions tend to admit a larger variety of opinion within them than denominations. Denominations encountering major differences of opinion within themselves are likely to split; this option is not open for most state churches, so they tend to try to integrate differing opinions within themselves. An exception to this is the Church of Scotland which has split several times in the past for doctrinal reasons. Its largest surviving offshoots are the Free Church of Scotland and the United Free Church of Scotland. These offshoots have lost the established status of their parent.
Increasingly, sociologists of religion are using the concept of monopolies in economics as an analogy for state churches.
State religions tend to enjoy the allegiance of the majority of their country; however much of this support is little more than nominal, with many members of the church rarely attending it. But the population's allegiance towards the state religions is often strong enough to prevent them from joining competing religious groups. Sociologists put this forward as an explanation for the religious differences between the United States and Europe: many sociologists theorise that the continuing vitality of religion in American life, compared to many European countries, is due to the lack of a strong state church (or indeed, any state church at all) during much of American history.
Just because a country has an official religion does not make that country intolerant towards other religions. It all depends upon the government and the level of tolerance the citizens of that country have for each other. Some countries with official religions have laws that guarantee the freedom of worship, full liberty of conscience, and places of worship for all citizens and implement those laws in society better than countries that do not have an official or established state religion.
Disestablishment is the process of divesting a church of its status as an organ of the state. In England there was a campaign by Liberals, dissenters and nonconformists to disestablish the Church of England in the late 19th century; it failed in England but demands for the measure persist to this day. The Church of Ireland was disestablished in 1869 and the Church of England was disestablished in Wales in 1920, becoming the Church in Wales. Those who wish to continue with an established church take a position of antidisestablishmentarianism.
The First Amendment to the Constitution of the United States explicitly bans the Federal government from setting up a state church. Until the mid-19th century this amendment was understood as allowing for state governments to create established churches and a number of states did so. With the passage of the Fourteenth Amendment, the prohibition on established churches was interpreted as a general prohibition on state support of religion. The exact boundaries of this prohibition are still disputed and are a frequent source of cases before the Supreme Court of the United States, especially as the court must reconcile the establishment clause of First Amendment with the clause that prohibits restraints on the free exercise of religion.
The following states which recognize some form of Christianity as their official religion:
States which recognize Catholicism as their official religion:
Nations which recognize a form of Protestant Christianity as their official religion:
Nations which recognize the Evangelical Lutheran Church as their official religion:
Nations which recognize the Orthodox Church as their official religion:
Countries which recognize Islam as their official religion:
Nations which recognize Sunni Islam as their official religion:
Countries which recognize Buddhism as their official religion:
Countries which recognize Lamaistic Buddhism as their official religion:
Country which recognizes Theravada Buddhism as their official religion:
Country which recognizes Hinduism as their official religion:
Established churches and former state churches in Europe
 In 1967, the Albanian government made atheism the "state religion". This designation remained in effect until 1991.
Former state churches in British North America