In Ireland, there is officially a separation of state and church, and the constitution prohibits the promotion of religion.

An excerpt from the article 39 facts about Ireland

The largest religious community is the Irish Roman Catholic Church - with 3.73 million believers.

In 2016, 78.3% of the population declared Catholicism, but the absolute number of Catholics, despite a decrease compared to data from 2002, increased thanks to the influx of immigrants from Poland and Lithuania.

An equally large group are people defining themselves as "without religion" - over 10%.