Ancient territories of Ireland
province (modern)
county (modern)
clan & family
Uí Mhaine Connacht comprised parts of Galway, Mayo and Roscommon the territory ó Muireadhaigh 
Iar Connacht Connacht comprised mainly Connemara, Mayo, Sligo The ancient chiefs of Moylurg 
Anaghaile (Annaly) Leinster comprised Longford the territory of ó Fearghail, ó Cuinn 
Déise (Decies) Leinster comprised west Waterford 
Naas Leinster Meath HY- KINSELLAGH AND CUALAN 
Ossory  Leinster Kilkenny, King's, and Queen's Counties [Offaly, Leix] 
Ur Mhumhan (Ormond) Leinster-Munster comprised part of Kilkenny and north Tipperary The ó Cinnéide became Lords of Ormond after being driven out of Clare 
Breifne (Breffny)  Leinster-Ulster comprised Cavan and western Leitrim the territory of ó Raghallaigh 
Principal Ulster Leinster-Ulster Ancient Oriel, Louth The Clan Colla 
Corcu Lóighdhe Munster comprised south west Cork the territory of ó Ceallaigh, ó Ceallacháin 
Deas Mhumhan (Desmond) Munster comprised part of Cork and Kerry The ó Súilleabháin established themselves in the west of Desmond. 
Muscraidhe (Muskerry) Munster comprised central and north west Cork 
Thuas Mhumhan (Thomand) Munster comprised Clare and Limerick the territory of the Dál gCais septs such as ó Briain 
Dál Riada Ulster comprised north Antrim The ó Loingsigh were driven from here after the Cambro Norman invasion 

Orghialla (Oriel)

Ulster comprised Armagh, Monaghan and parts of south Down, Louth and Fermanagh 
Fermanagh Ulster Fermanagh 
Tir Chonaill (Tyrconnel) Ulster comprised west Donegal the territory of ó Domhnaill, ó Baoighill, ó Gallchobhair. As the Mac Lochlainn declined in power the ó Dochartaigh a leading sept of the Cineál Chonaill became rulers of Inishowen. 
Tir Eoghain (Tir-Owen) Tyrone Ulster  comprised Tyrone and the barony of Loughshinlon in Derry the territory of the ó Néill. The original territory was Inis Eoghain the chief sept of which was the Mac Lochlainn 
Ulidia  Ulster comprised Down, Antrim 

Historic Highlands
Historic Lowlands
Southern Uplands