Religion in the Republic of Ireland
The predominant religion in the Republic of Ireland is Christianity, with the largest church being the Roman Catholic Church. The Irish constitution says that the state may not endorse any particular religion and guarantees freedom of religion.
Northern Ireland
At the 2011 census, 41.5% of the population identified as Protestant/non-Roman Catholic Christian, 41% as Roman Catholic, and 0.8% as non-Christian, while 17% identified with no religion or did not state one. The biggest of the Protestant/non-Roman Catholic Christian denominations were the Presbyterian Church (19%), the Church of Ireland (14%) and the Methodist Church (3%). In terms of community background (i.e. religion or religion brought up in), 48% of the population came from a Protestant background, 45% from a Catholic background, 0.9% from non-Christian backgrounds, and 5.6% from non-religious backgrounds.