The following ancient territories, were in existence from prehistoric times to the break-up the Gaelic order in the sixteenth century:

Breffny (Breifne): Cavan and west Leitrim.

Corca Laoidhe: South-west Cork.

Dalriada: North Antrim.

Decies (D�ise): West Waterford.

Desmond (Deasmhumhan): Kerry and much of Co. Cork.

Iar Connacht: West Connacht, mainly Connemara.

Muskerry (Muscraidhe) North-west and central Cork.

Oriel (Orghialla): Cos. Armagh and Monaghan and parts of south Down, Louth and Fermanagh.

Ormond (Urmhumhan): Much of Co. Kilkenny and north Tipperary.

Ossory: The extent of the ancient kingdom of Osraighe was apporoximately the same as that of the diocese of Ossory, ie. Co. Kilkenny and some adjacent areas.

Thomond (Tuathmhumhan): Most of Co. Clare with adjacent parts of Cos. Limerick and Tipperary.

Tirconnell (Tir Chonaill): Co. Donegal.

Tirowen (Tir Eoghain): Co. Tyrone with adjacent part of Co. Derry.