O Donegan or O Dunnigan - Irish / Ua Donnagain. Important Heremonian Ui Cobhthaigh Ui Conaire Muscraige Tri Maighe Sept / Family branch, who had their territory in the north - west of Co. Cork in (Muskerry of the 3 Plains) O Donegans Country in Des Mhumhain /  Desmond / Southern Munster, which was eventually taken over by the Barrys who were Anglo - Norman Barons there. See also O Dongan. Ancestors:*69.Conaire 11 (Ui Conaire) the 111th King of Tara / Ireland, *60.Coffey / Cobhthach the 69th King of Tara / Erinn, *37.Eremon (Heremonians).

O Donegan or O Dunnigan - Irish / Ua Donnagain. An Erenagh Sept / Family branch, who had their territory in the south - west of Co. Cork around Beare in Des Mhumhain / Desmond / Southern Munster, which eventually came under the over lordship of the O Sullivans. See also O Dongan.

O Donegan or O Dunnigan - Irish / Ua Donnagain. A Sept / Family branch, who had their territory in Co. Roscommon in the east of the Connacht Province.

O Donegan or O Dunnigan - Irish / Ua Donnagain. A Sept / Family branch, who had their territory in the north of Co. Tipperary in the north - east of Aur Mhumhain / Ormond / Eastern Munster and the adjacent territory in Co. Limerick under Rory O Donnagain the King of Aradh eventually given over to the Mac I Brian of Ara, a son of *105.Brian Boru the King of Thomond, 41st King of Munster and 175th High King of Ireland.

O Donegan or O Donnegan or O Donnegane or O Dunnigan - Irish / Ua Donnagain. Heremonian Dal Cuinn Colla Da Crioch Cenel Rochada Fernmag (Fer Fermaighe / Farney Sept / Family branch who had their territory in Co. Monaghan in Southern Ulster. Now also indistinguishable from Mac Donegan. Ancestors:  *86.Cairbre Liffeachair the 117th King of Tara / Ireland. 87.Eochy / Echu Doimhlen, 88.Murray / Muireadach Colla Da Crioch / Focrith - of the Two Countries, 89.Rochad / Rochatha, 90.Dega Duirn, 91.Feicc,  92.Criffan Leith / Crimthainn Lethan, 93.Eochy / Echach, 94.Cairpre Daim Argait, 95.Nadsluaig, 96.Fergus, 97.Cronan, 98.Maoilfothartaigh, 99.Mailduib, 100.Aitheachda, 101.Artrach, 102.Maoilfothartaigh,  103.Ruadrach, 104.Fogartach, 105.Duncan / Donncuan, 106.Fogartach, 107.Laidgnen, 108.Murray / Muireadach,  109.Fogartach, 110.Lethlobar,  

O Donegan or O Dunnigan - Irish / Ua Donnagain. A Sept / Family branch of the Crioch Dungan, who had their territory in Co. Westmeath in the south - west of Northern Leinster and adjacent territory in Co. Laois, Co. Offaly and Co. Kildare in Southern Leinster. Thomas Donegan was at one time the English appointed Earl of Limerick.

O Donegan - Irish / Ua Donnagain. Heremonian Dal Cuinn Sept / Family branch who had their territory in Co. Donegal in the Ulster Province who were the Chiefs of Tir Breasail with the Mac Giblins.

Mac Donegan - Irish / Mac Donnagain. A Sept / Family branch, who had their territory in Co. Down in the south - east of the Ulster Province. See also Dongan.

Donel -

O Donelan. Heremonian Ui Cobhthaigh Ui Felim Dal Cuinn Colla Mac Uais Ui Mheic Uais Ui Tuitre Sept / Family branch, who had their territory in the west of Loch Neagh in Co. Tyrone in Central Ulster and north - west of the loch at Loughinsholin in Co. Derry. Ancestors: *88.Carroll / Carioll Colla Uais the 121st King of Tara / Ireland, 87.Eochy / Echu Doimhlen, *86.Cairbre Liffeachair the 117th King of Tara / Ireland. See especially O Donnellan.

O Donevan. A Sept / Family branch, who had their territory in Co. Limerick in the mid - north - west of Tuaisceart Mhumhain / Thomond / Northern Munster.

Dongan. English Earls in Co. Limerick in the mid - north - west of Thomond / Northern Munster and were also in Co. Kildare in Central Southern Leinster and Co. Dublin in the north - east of Southern Leinster.

O Donlan or O Donnellan, which see - Irish / Ua Domhnallain. Heremonian Dal Cuinn Colla da Crioch Ui Maine Sept / Family branch, who had their territory in the south - east of Co. Galway in Southern Connacht. Ancestors: *83.Conn - of the Hundred Battles the 110th King of Tara / Ireland (Dal Cuinn).

O or Mac Donlevy or O or Mac Dunlevy, which see - Irish / Mheic Duinnshliebhe. (Descended from a son of 109.Donn Sliebe) Dal Fiatach Sept / Family branch who were Princes / Tanaistes originally in their territory in Co. Down in the south - east of the Ulster Province where their territory was the kingdom of Ulaidh from which Ulster received its name. Later on they had their territory  in Co. Tyrone in Central Ulster. Ancestors: 109.Donn Sliebe the 56th King of Ulaid, 108.Eochy / Eochaidh the 52a King of Ulaid, 107.Niall the 52nd King of Ulaid, 106.Eochy / Eochaidh the 45th King of Ulaid, 105.Ardgal the 42nd King of Ulaid, 104.Matudan the 41st King of Ulaid, 103.Aed the 37th King of Ulaid, 102.Eochocan the 31st King of Ulaid, 101.Aed, 100.Eochy / Eochaidh the 24th King of Ulaid, 99.Fiachnae the 22nd King of Ulaid, 98.Aed Rain the 19th King of Ulaid, 97.Becc Bairrche the 17th King of Ulaid, 96.Blathmac the 14th King of Ulaid, 95.Mael Cobo the 13th King of Ulaid, 94.Fiachnae the 10th King of Ulaid, 93.Demman the 6th King of Ulaid, 92.Cyril / Cairell the 3rd King of Ulaid, 91.Murray / Muireadach the 1st Dal Fiatach King of Ulaid, 90.Forgg mac Dallain.

O Donnan - Irish / Ua Donnain. A Sept / Family branch, who had their territory in Co. Down in the south - east of the Ulster Province. Often confused with O Doonan.

O Donnegan - Irish / Ua Dhonnagain. A Sept / Family branch, who had their territory in Co. Fermanagh in the south - west of the Ulster Province and were Chiefs in Co. Tyrone in Central Southern Ulster and Co. Armagh in the south - east of Ulster.

O Donnegan - Irish / Ua Dhonnagain. A Sept / Family branch, who had their territory in Co. Tipperary in the north - east of Aur Mhumhain / Ormond /  North Eastern Munster where they were Princes / Tanaistes and kinsmen to the O Gleeson / O Glissane there.