Ireland is still a majority Catholic country, but less so with every census. In the 2022 census, 69% of people in the Republic (about 3.5 million) said they were Roman Catholic, 14% (736,210 people) said they had no religion, 2.1% were Orthodox Christians and about 2% belonged to the Church of Ireland. Muslims numbered about 83,000 and Hindus 33,043. The state has no official religion. Article 44 of the 1937 Constitution guarantees freedom of religion and bars the state from endowing any faith, and the clause giving the Catholic Church a "special position" was deleted by referendum in 1972. Belief is not spread evenly, though, so this guide goes region by region and looks at who worships where, and why.
Dublin: Where Ireland’s Minority Faiths Cluster
Ireland's religious minorities are most concentrated in the capital. Of the roughly 83,000 Muslims in the 2022 census, 37,458 lived in Dublin city and its suburbs, more than eight times the figure for Cork. The community dates its organised history to 1959, when students founded the Dublin Islamic Society. The first mosque opened in 1976 in a four-storey building at 7 Harrington Street. In 1983 the society moved to 163 South Circular Road, which is still the Dublin Mosque. The largest complex is the Islamic Cultural Centre of Ireland in Clonskeagh, beside University College Dublin, which President Mary Robinson opened on 16 November 1996. Dublin also has the country's main Sikh gurdwara, Guru Nanak Darbar, which hosts a Nagar Kirtan parade at Vaisakhi. Ireland's Jewish community, 2,193 people in 2022, is far older: Jewish presence was first recorded in the Annals of Inisfallen in 1062.
Dublin is also the historic centre of Irish Protestantism. The city has two Church of Ireland cathedrals about 400 metres apart. Christ Church holds the archbishop's seat, and St Patrick's has been the church's national cathedral since 1870, with a deanship that Jonathan Swift once held. The Catholic archdiocese is just as visible, yet practice in the city has fallen furthest. In 2011 weekly Mass attendance in Dublin averaged about 18%, and in some parishes it was below 2%. Orthodox Christians, mostly immigrants from Romania, Russia and Ukraine, are the other big newcomers: Orthodoxy has been the fastest-growing religion in the state since 1991, served by Greek, Romanian and Russian parishes. If you want to know how Dublin fits into the state's institutions, our guide to the government of Ireland covers the Oireachtas and the presidency.
Glendalough and Maynooth: Leinster's Monastic and Seminary Heartland
South of Dublin, in the glacial valleys of County Wicklow, is Glendalough, the "valley of two lakes". St Kevin founded a monastery there in the 6th century and died in about 618. The settlement thrived for six centuries. At the Synod of Ráth Breasail in 1111 Glendalough became one of the two dioceses of North Leinster, and its best-known abbot, Laurence O'Toole, became Archbishop of Dublin in 1162. Today its round tower and stone churches draw walkers and pilgrims alike.
West of Dublin, Maynooth in County Kildare tells a later chapter. The Fitzgerald Earls of Kildare founded a college there early in the 16th century, and it was suppressed in 1535 at the Reformation. The present Royal College of St Patrick was set up by the Maynooth College Act of 1795, as the penal laws were being eased, so that Irish priests no longer had to train in continental Europe. It was built for up to 500 students and was once the largest seminary in the world. In 1896 it received a pontifical charter to award degrees in theology, philosophy and canon law. It is still the national seminary, though it now shares its campus with the state-run Maynooth University.
Clonmacnoise and the Shannon Midlands
Where the Esker Riada, a glacial ridge that carried the old east-west road across the bogs, meets the River Shannon south of Athlone, St Ciarán founded Clonmacnoise in 544. Its position made it one of the great centres of learning, craftsmanship and trade in Ireland by the 9th century. Many High Kings of Tara and kings of Connacht were buried there. It was largely abandoned by the end of the 13th century, but nine ruined churches, two round towers and a large number of carved stone crosses survive in County Offaly. Its graveyard is still in use, and services are held in a modern chapel.
The midland towns show how newer faiths have spread well beyond the cities. The 2022 census counted 810 Muslims in Portlaoise, 615 in Athlone, 497 in Mullingar and 402 in Longford. These numbers are small, but they come from a faith that made up only 0.1% of the state's population as recently as 1991.
Mayo and Galway: Knock, Croagh Patrick and the Mosque at Ballyhaunis
The west holds Ireland's busiest Catholic pilgrimage sites. On the wet evening of 21 August 1879, villagers in Knock, County Mayo, said they saw the Virgin Mary, St Joseph and St John the Evangelist at the gable of their parish church. Statements were taken from 15 witnesses, and the Knock Shrine became the national Marian shrine. At the closing of the 1932 Eucharistic Congress, Pope Pius XI declared Our Lady of Knock "Queen of Heaven and of Ireland".
Above Clew Bay near Westport rises Croagh Patrick, 764 m (2,507 ft) high. St Patrick is said to have fasted for forty days on its summit, and there has been a church at the top since the 5th century. Every year on Reek Sunday, the last Sunday in July, thousands of pilgrims climb it. The custom goes back at least to the Middle Ages.
Mayo is also where the religious map breaks pattern. Ballyhaunis, a town of 2,773 people in 2022, has Ireland's first purpose-built mosque, which was also the first mosque outside Dublin. In the 2011 census, 42% of the town's residents were non-Irish nationals, the highest share of any Irish town, and Poles and Pakistanis were the largest groups. By 2016 about 23% of its people were Muslim. In Galway city, Catholic confidence of an earlier era is set in limestone. Galway Cathedral was built between 1958 and 1965 on the site of the old Galway Gaol. It opened on 15 August 1965, when President Éamon de Valera lit the sanctuary candle, and it is often called the last great stone cathedral built in Europe.
Cork, Limerick and Tipperary: Munster's Cathedrals and the Rock of Cashel
Munster's spiritual landmark is the Rock of Cashel in County Tipperary, a rock outcrop that rises steeply above the plain. According to the Tripartite Life of St Patrick, the saint converted the King of Munster there in the 5th century. Brian Boru was crowned at Cashel in 977, and in 1101 King Muirchertach Ua Briain gave the fortress to the Church.
The province also has deep roots in the mendicant orders. The Franciscans' first Irish house was at Youghal in County Cork in 1224 or 1226, and the O'Briens later founded Ennis Friary in County Clare. In Cork city, Saint Fin Barre's Cathedral, a three-spired Gothic Revival building designed by William Burges, was begun in 1863 on a site where, according to local lore, Finbarr founded a monastery in the 7th century. It belongs to the Church of Ireland, a reminder that Protestant congregations survived across the south even after numbers fell. The newest communities are clustered in Munster's cities. The 2022 census counted 4,535 Muslims in Cork, 3,394 in Limerick, 2,084 in Waterford and 980 in Tralee. Cork's Muslim community has long prayed in halls on housing and industrial estates while raising money for a purpose-built mosque.
East Donegal and Inishowen: Where Irish Protestantism Is Most Rooted
Most Protestants on the island live in the nine-county province of Ulster. Inside the Republic, the main concentrations are in east Donegal and the Inishowen peninsula. The pattern dates to the Plantation of Ulster, which followed the Flight of the Earls in 1607. Land across Donegal, Cavan, Fermanagh, Tyrone, Armagh and Londonderry passed to the Crown and was settled with English and Scottish Protestants. Their descendants explain why Ulster Scots is still spoken in Donegal's Finn Valley and Laggan district, and why Presbyterian and Church of Ireland congregations are more rooted along the Donegal border than in most of the south. Our guide to the Northern Ireland border explains how partition drew the line through this landscape.
Partition in 1922 left the south 92.6% Catholic and 7.4% Protestant. By the 1960s the Anglican and Nonconformist population had fallen by half, mostly through emigration in the early years of independence. The Catholic Church's Ne Temere decree, which required the children of mixed marriages to be raised Catholic, was a further grievance. The Protestant population has since recovered to more than 200,000 through immigration and some conversion. The Church of Ireland itself had stopped being the state church in 1871 under the Irish Church Act 1869. It is still organised on an all-island basis and led from Armagh. Donegal is also home to an ancient penitential pilgrimage site, St Patrick's Purgatory on Station Island in Lough Derg. Texts mention it as early as 1185, and it is the only Irish site marked on Martin Behaim's world map of 1492.
From 94.9% to 69%: The Shift That Runs Across Every Region
Under all these regional differences runs one national trend. Catholic identification peaked at 94.9% in the 1961 census and has fallen at every count since, to 84.2% in 2011, 79% in 2016 and 69% in 2022. The number with no religion rose by 63% between 2016 and 2022. It was highest among 25 to 29-year-olds, 26% of whom ticked "no religion", and 16% of children under five were recorded with none. For 2022 the Central Statistics Office changed the question to "What is your religion, if any?" and listed "No religion" first.
Practice has fallen faster than identity. Surveys recorded weekly Mass attendance of about 91% in the 1970s, 85% in 1990 and 48% by 2006. A World Inequality Database study found that the share of adults attending church at least monthly dropped from 80% in the 1990s to 28% in 2020. The referendums that legalised same-sex marriage in 2015 and abortion in 2018, both passed over the objections of the Catholic hierarchy, are often read as the political side of the same change. Even so, the map has not been wiped clean. Reek Sunday still fills the slopes above Clew Bay, Lough Derg still receives penitents, and a large share of schools are still run by religious bodies, though the state's Education and Training Boards announced in 2020 that they would phase out mandatory graduation Masses in their multidenominational schools. To see how these counties and provinces fit together on the ground, read our guide to Ireland's regions and geography.