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.
Religion in Northern Ireland
The Roman Catholic Church in Ireland is the largest single church, though there is a greater number of Protestants overall. The Church is organised into four provinces though these are not coterminous with the modern political division of Ireland. The seat of the Archbishop of Armagh, the Primacy of Ireland, is St. Patrick's Cathedral, Armagh.