The geographical sub-divisions used in this report are based on Regional Authorities. These eight regions were established under the Local Government Act, 1991 (Regional Authorities) (Establishment) Order, 1993 which came into operation on 1 January, 1994.
| Name of region | Constituent counties | Type of area |
| Border | Cavan | Administrative county |
| Donegal | Administrative county | |
| Leitrim | Administrative county | |
| Louth | Administrative county | |
| Monaghan | Administrative county | |
| Sligo | Administrative county | |
| Dublin | Dublin | City |
| Dún Laoghaire-Rathdown | Administrative county | |
| Fingal | Administrative county | |
| South Dublin | Administrative county | |
| Mid-East | Kildare | Administrative county |
| Meath | Administrative county | |
| Wicklow | Administrative county | |
| Midland | Laoighis | Administrative county |
| Longford | Administrative county | |
| Offaly | Administrative county | |
| Westmeath | Administrative county | |
| Mid-West | Clare | Administrative county |
| Limerick | City | |
| Limerick | Administrative county | |
| Tipperary North Riding | Administrative county | |
| South-East | Carlow | Administrative county |
| Kilkenny | Administrative county | |
| Tipperary South Riding | Administrative county | |
| Waterford | City | |
| Waterford | Administrative county | |
| Wexford | Administrative county | |
| South-West | Cork | City |
| Cork | Administrative county | |
| Kerry | Administrative county | |
| West | Galway | City |
| Galway | Administrative county | |
| Mayo | Administrative county | |
| Roscommom | Administrative county | |
| For the 1991 and previous censuses, the geographical sub-divisions used were Planning Regions. | ||
