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.
Protestantism in Ireland
The Protestant depopulation in the Republic of Ireland during 1891-1991 was dramatic. Establishment of the Irish Free State in 1922 may have further accelerated this phenomenon as many Protestants were wary of living in a majority Catholic country and therefore chose to emigrate to the United Kingdom. In 1861 only the west coast and Kilkenny were less than 6% Protestant. Dublin and two of the 'border counties' were over 20% Protestant. In 1991, however, all but four counties were less than 6% Protestant; the rest were less than 1%. There were no counties in the Republic of Ireland which had experienced a rise in the relative Protestant population over the period 1861 to 1991. Often, the counties which managed to retain the highest proportion of Protestants were the ones which started off with a large proportion. In Northern Ireland, only counties Londonderry, Tyrone and Armagh have experienced a significant loss of the relative Protestant population; in these cases, the change was not as dramatic as in the Republic.