Catholic Church in Ireland
In the 2016 Irish census 78.3% of the population identified as Catholic in Ireland; numbering approximately 3.7 million people. Unlike Catholics in the United States, Ireland has seen a significant decline from the 84.2% who identified as Catholic in the 2011 census.
Christianity in Ireland
Christianity is and has been the largest religion in Ireland. Most Christian churches are organized on an all-Ireland basis, including both the Republic of Ireland and Northern Ireland. In the Republic of Ireland, 78.3% of the population adheres to the Catholic Church. In Northern Ireland, the various branches of Protestantism collectively form a plurality of the population but the single largest church is the Catholic Church which accounts for some 40.8% of the population.