Catholic DiocesesinIreland | ![]() |
| Former Jurisdiction | Type | Became |
| Achonry Achaden(sis) | Abbacy nullius | Now Diocese of Killala |
| Aghaboe | Diocese | Now Diocese of Ossory |
| Aghaboe | Abbacy nullius | Now Diocese of Ossory |
| Aghadoe | Abbacy nullius | Suppressed into Diocese of Kerry |
| Annaghdown / Eanach Dúin | Diocese | Now Metropolitan Archdiocese of Tuam and Titular Episcopal See of Eanach Dúin |
| Annaghdown / Eanach Dúin | Abbacy nullius | Now Metropolitan Archdiocese of Tuam and Titular Episcopal See of Eanach Dúin |
| Ardagh Ardachaden(sis) | Abbacy nullius | Now Diocese of Ardagh |
| Ardcarne Ardcarnen(sis) | Abbacy nullius | Now Diocese of Elphin and Titular Episcopal See of Ardcarne |
| Ardfert Ardferten(sis) | Abbacy nullius | Now Diocese of Kerry |
| Ardfert and Aghadoe / Kerry and Aghadoe Ardferten(sis) et Aghadonen(sis) / Kerrien(sis) et Aghadonen(sis) | Diocese | Now Diocese of Kerry |
| Ardfert and Aghadoe / Kerry and Aghadoe Ardferten(sis) et Aghadonen(sis) / Kerrien(sis) et Aghadonen(sis) | Diocese | Now Diocese of Kerry |
| Ardmore Ardmorn(sis) | Diocese | Now Diocese of Lismore and Titular Episcopal See of Ardmore |
| Ardmore Ardmorn(sis) | Abbacy nullius | Now Diocese of Lismore and Titular Episcopal See of Ardmore |
| Armagh Armachan(us) | Archdiocese | Now Metropolitan Archdiocese of Armagh |
| Brefinnia Tybruinen(sis) | Diocese | Now Diocese of Kilmore |
| Brefinnia | Abbacy nullius | Now Diocese of Kilmore |
| Cashel Cashelien(sis) / Cassilien(sis) | Metr. Archdiocese | Now Metropolitan Archdiocese of Cashel and Emly |
| Cashel Cashelien(sis) / Cassilien(sis) | Diocese | Now Metropolitan Archdiocese of Cashel and Emly |
| Ceanannus Mór Cenanen(sis) | Diocese | Now Diocese of Meath and Titular Episcopal See of Ceanannus Mór |
| Ceanannus Mór Cenanen(sis) | Abbacy nullius | Now Diocese of Meath and Titular Episcopal See of Ceanannus Mór |
| Cinél nEógain and Ardstraw | Diocese | Now Diocese of Derry |
| Clogher Clogherien(sis) | Abbacy nullius | Now Diocese of Clogher |
| Clonard | Diocese | Now and Titular Episcopal See of Cluain Iraird |
| Clonard | Diocese | Now and Titular Episcopal See of Cluain Iraird |
| Clonard | Abbacy nullius | Now and Titular Episcopal See of Cluain Iraird |
| Clonfert Clonferten(sis) | Abbacy nullius | Now Diocese of Clonfert |
| Clonmacnois Cluanen(sis) | Diocese | United with Diocese of Ardagh |
| Clonmacnois Cluanen(sis) | Abbacy nullius | United with Diocese of Ardagh |
| Cloyne Cloynen(sis) | Diocese | Now Diocese of Cork and Ross |
| Cloyne Cloynen(sis) | Abbacy nullius | Now Diocese of Cork and Ross |
| Cloyne and Ross Cloynen(sis) et Rossen(sis) | Diocese | Now Diocese of Cork and Ross |
| Cong Congen(sis) | Diocese | Now Metropolitan Archdiocese of Tuam and Titular Episcopal See of Cunga Féichin |
| Cong Congen(sis) | Abbacy nullius | Now Metropolitan Archdiocese of Tuam and Titular Episcopal See of Cunga Féichin |
| Connor Connoren(sis) | Diocese | Suppressed into Diocese of Down and Connor |
| Connor Connoren(sis) | Abbacy nullius | Suppressed into Diocese of Down and Connor |
| Cork Corcagien(sis) | Diocese | Now Diocese of Cork and Ross |
| Cork Corcagien(sis) | Diocese | Now Diocese of Cork and Ross |
| Cork Corcagien(sis) | Abbacy nullius | Now Diocese of Cork and Ross |
| Cork and Cloyne Corcagien(sis) et Cloynen(sis) | Diocese | Now Diocese of Cork and Ross |
| Derry | Abbacy nullius | Now Diocese of Derry |
| Dublin Dublinen(sis) | Diocese | Now Metropolitan Archdiocese of Dublin |
| Duleek Davligen(sis) | Diocese | Now Titular Episcopal See of Cluain Iraird and Titular Episcopal See of Duleek |
| Duleek Davligen(sis) | Abbacy nullius | Now Titular Episcopal See of Cluain Iraird and Titular Episcopal See of Duleek |
| Dunshaughlin / Domnach Sechnaill | Abbacy nullius | Now Titular Episcopal See of Cluain Iraird and Titular Episcopal See of Domnach Sechnaill |
| Elphin Elphinen(sis) | Diocese | Now Diocese of Elphin |
| Elphin Elphinen(sis) | Abbacy nullius | Now Diocese of Elphin |
| Emly Emelien(sis) | Diocese | Suppressed into Metropolitan Archdiocese of Cashel and Emly |
| Ferns Fernen(sis) | Abbacy nullius | Now Diocese of Ferns |
| Galway Galvien(sis) | Diocese | Now Diocese of Galway and Kilmacduagh |
| Glendalough / Easpuig Gleann Dá Loch / Glenndálocha Glendalacen(sis) | Diocese | Now Metropolitan Archdiocese of Dublin and Titular Episcopal See of Glenndálocha |
| Glendalough / Easpuig Gleann Dá Loch / Glenndálocha Glendalacen(sis) | Diocese | Now Metropolitan Archdiocese of Dublin and Titular Episcopal See of Glenndálocha |
| Glendalough / Easpuig Gleann Dá Loch / Glenndálocha Glendalacen(sis) | Diocese | Now Metropolitan Archdiocese of Dublin and Titular Episcopal See of Glenndálocha |
| Glenndálocha | Abbacy nullius | Now Metropolitan Archdiocese of Dublin and Titular Episcopal See of Glenndálocha |
| Inniscathy Insulæ Cathen(sis) | Diocese | Now Diocese of Kerry, Diocese of Killaloe, Diocese of Limerick and Titular Episcopal See of Inis Cathaig |
| Inniscathy Insulæ Cathen(sis) | Abbacy nullius | Now Diocese of Kerry, Diocese of Killaloe, Diocese of Limerick and Titular Episcopal See of Inis Cathaig |
| Kildare Daren(sis) / Kildarien(sis) | Diocese | Now Diocese of Kildare and Leighlin |
| Kildare Daren(sis) / Kildarien(sis) | Abbacy nullius | Now Diocese of Kildare and Leighlin |
| Kilfenora Fenaboren(sis) | Diocese | United with Diocese of Galway and Kilmacduagh |
| Kilfenora Fenaboren(sis) | Abbacy nullius | United with Diocese of Galway and Kilmacduagh |
| Killala Alladen(sis) | Abbacy nullius | Now Diocese of Killala |
| Killaloe Laonien(sis) | Abbacy nullius | Now Diocese of Killaloe |
| Killashee Cellæ Sanctii Auxilii | Abbacy nullius | Now Diocese of Kildare and Leighlin and Titular Episcopal See of Cell Ausaille |
| Kilmacduagh Duacen(sis) | Diocese | Suppressed into Diocese of Galway and Kilmacduagh |
| Kilmacduagh Duacen(sis) | Abbacy nullius | Suppressed into Diocese of Galway and Kilmacduagh |
| Leighlin Leighlien(sis) | Diocese | Suppressed into Diocese of Kildare and Leighlin |
| Leighlin Leighlien(sis) | Abbacy nullius | Suppressed into Diocese of Kildare and Leighlin |
| Lismore Lismorien(sis) | Diocese | Suppressed into Diocese of Waterford and Lismore |
| Lismore Lismorien(sis) | Abbacy nullius | Suppressed into Diocese of Waterford and Lismore |
| Louth | Abbacy nullius | Now Diocese of Clogher and Titular Episcopal See of Louth |
| Maghera, Cenél Fearadhaigh and Ardstraw | Diocese | Now Diocese of Derry |
| Mayo Magionen(sis) | Diocese | Now Metropolitan Archdiocese of Tuam and Titular Episcopal See of Mayo |
| Mayo Magionen(sis) | Abbacy nullius | Now Metropolitan Archdiocese of Tuam and Titular Episcopal See of Mayo |
| Raigh Maighe Beiscirt | Diocese | Now Diocese of Kerry |
| Raphoe Rapoten(sis) | Abbacy nullius | Now Diocese of Raphoe |
| Roscommon | Diocese | Now Diocese of Elphin |
| Roscrea Rosgren(sis) | Diocese | Now Diocese of Killaloe and Titular Episcopal See of Roscrea |
| Roscrea Rosgren(sis) | Abbacy nullius | Now Diocese of Killaloe and Titular Episcopal See of Roscrea |
| Ross Rossen(sis) | Diocese | Suppressed into Diocese of Cork and Ross |
| Ross Rossen(sis) | Abbacy nullius | Suppressed into Diocese of Cork and Ross |
| Saint Nicholas | Collegiate nullius | Now Diocese of Galway and Kilmacduagh |
| Seir Kieran | Abbacy nullius | Now Diocese of Ossory |
| Sléibhte / Sletty / Slebte Slebten(sis) | Abbacy nullius | Now Diocese of Kildare and Leighlin and Titular Episcopal See of Slebte |
| Trim | Abbacy nullius | Now Titular Episcopal See of Cluain Iraird and Titular Episcopal See of Ath Truim |
| Tuam Tuamen(sis) | Diocese | Now Metropolitan Archdiocese of Tuam |
| Tuam Tuamen(sis) | Abbacy nullius | Now Metropolitan Archdiocese of Tuam |
| Waterford Vaterfordien(sis) | Diocese | Now Diocese of Waterford and Lismore |
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