(Click on the column title to sort by that column)
| # | Catholics | Population | Percent Catholic | Province | Dioceses | Suffragans | Diocesan Priests | Religious Priests | Total Priests | Permanent Deacons | Male Religious | Female Religious | Parishes |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 1 | 1,336,000 | 2,359,000 | 56.63% | Armagh | 9 | Ardagh (and Clonmacnois), Clogher, Derry, Down and Connor, Dromore, Kilmore, Meath, Raphoe | 983 | 285 | 1,268 | 1 | 420 | 1,645 | 441 |
| 2 | 1,401,000 | 1,556,000 | 90.04% | Dublin | 4 | Ferns, Kildare and Leighlin, Ossory | 825 | 934 | 1,759 | 1,393 | 3,230 | 293 | |
| 3 | 966,000 | 1,001,000 | 96.50% | Cashel (-Emly) | 7 | Cloyne, Cork and Ross, Kerry, Killaloe, Limerick, Waterford and Lismore | 874 | 328 | 1,202 | 519 | 2,332 | 377 | |
| 4 | 396,000 | 407,000 | 97.30% | Tuam | 6 | Achonry, Clonfert, Elphin, Galway and Kilmacduagh, Killala | 436 | 87 | 523 | 139 | 878 | 201 |
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