| ISO-3166-2 | ISO Region | Fips | GN | Name of Subdivision | Type | Capital | Population | area in km² | lang | continent | From | Till |
| 1 | C | M | 04 | 04 | Cork  | county | Cork | | | | EU | | |
| 2 | CE | M | 03 | 03 | Clare  | county | Inis | 106,924 | | | EU | | |
| 3 | CN | U | 02 | 02 | Cavan  | county | An Cabhán | 57,473 | | | EU | | |
| 4 | CW | L | 01 | 01 | Carlow  | county | Ceatharlach | 47,393 | | | EU | | |
| 5 | D | L | | 07 | Dublin  | | Baile Átha Cliath | 1,146,503 | | | EU | | |
| 6 | DL | U | 06 | 06 | Donegal  | county | Leifear | 139,838 | | | EU | | |
| 7 | G | C | 10 | 10 | Galway  | county | Galway | 216,926 | | | EU | | |
| 8 | KE | L | 12 | 12 | Kildare  | county | An Nás | 177,574 | | | EU | | |
| 9 | KK | L | 13 | 13 | Kilkenny  | county | Cill Chainnigh | 82,284 | | | EU | | |
| 10 | KY | M | 11 | 11 | Kerry  | county | Trá Lí | 134,656 | | | EU | | |
| 11 | LD | L | 18 | 18 | Longford  | county | An Longfort | 31,308 | | | EU | | |
| 12 | LH | L | 19 | 19 | Louth  | county | Dún Dealgan | 105,295 | | | EU | | |
| 13 | LK | M | 16 | 16 | Limerick  | county | Limerick | 179,071 | | | EU | | |
| 14 | LM | C | 14 | 14 | Leitrim  | county | Cora Droma Rúisc | 25,895 | | | EU | | |
| 15 | LS | L | 15 | 15 | Laois  | county | Port Laoise | 60,804 | | | EU | | |
| 16 | MH | L | 21 | 21 | Meath  | county | Baile Átha Troim | 144,185 | | | EU | | |
| 17 | MN | U | 22 | 22 | Monaghan  | county | Muineachán | 53,085 | | | EU | | |
| 18 | MO | C | 20 | 20 | Mayo  | county | Castlebar | 119,089 | | | EU | | |
| 19 | OY | L | 23 | 23 | Offaly  | county | Tullamore | 65,231 | | | EU | | |
| 20 | RN | C | 24 | 24 | Roscommon  | county | Ros Comáin | 54,174 | | | EU | | |
| 21 | SO | C | 25 | 25 | Sligo  | county | Sligeach | 58,900 | | | EU | | |
| 22 | TA | M | | 26 | Tipperary  | | Clonmel | | | | EU | | |
| 23 | WD | M | 27 | 27 | Waterford  | county | Port Láirge | 104,132 | | | EU | | |
| 24 | WH | L | 29 | 29 | Westmeath  | county | An Muileann gCearr | 75,298 | | | EU | | |
| 25 | WW | L | 31 | 31 | Wicklow  | county | Cill Mhantáin | 119,873 | | | EU | | |
| 26 | WX | L | 30 | 30 | Wexford  | county | Loch Garman | 121,122 | | | EU | | |
| 27 | | | 32 | 32 | Cork City | city [English] / cathair [Irish] | | | | | EU | | |
| 28 | | | 33 | 33 | Dublin City | city [English] / cathair [Irish] | | | | | EU | | |
| 29 | | | 34 | 34 | Dún Laoghaire-Rathdown | county | | | | | EU | | |
| 30 | | | 35 | 35 | Fingal | county | | | | | EU | | |
| 31 | | | 36 | 36 | Galway City | city [English] / cathair [Irish] | | | | | EU | | |
| 32 | | | 37 | 37 | Limerick City | city [English] / cathair [Irish] | | | | | EU | | |
| 33 | | | 38 | 38 | North Tipperary | county | | | | | EU | | |
| 34 | | | 39 | 39 | South Dublin  | county | | | | | EU | | |
| 35 | | | 40 | 40 | South Tipperary | county | | | | | EU | | |
| 36 | | | 41 | 41 | Waterford City | city [English] / cathair [Irish] | | | | | EU | | |