My research into the Origins of the surname KERNAGHAN involved the review of some ancient and other texts, such as “The Four Masters - Annals of the Kingdom of Ireland” (see below), as well as of material on various websites. As can be evidenced from the commentary below, it is clear that the Kernaghans were an ancient Irish Clann, initially in the KINGDOM OF MEATH   and later in the COUNTY OF DONEGAL and were quite powerful at various stages of Ireland's medieval history. 

KERNAGHAN (and its variants) is the anglicised version of the Gaelic name O CEARNACHAIN, which derives from the Gaelic word ‘cearnach’ meaning  ‘victorious’.

It is accepted that Ireland was the first society in Europe to adopt the hereditary name. This was from the late 10th Century with the adoption of surnames replacing the earlier practice of patronymic naming (e.g. Tadhg, son of Cearnachan). The structure of these surnames was invariably prefixed (Mac or Mc meaning Son of – and - O or Ua meaning Descendant of (usually grandson or great-grandson ). The substantive prefix ‘Ua’ eventually became replaced by ‘O’ from the 1300's onwards.  


The first record of surname UA CEARNACHAIN is in Meath in 1012AD when                                                                                                                    “Maelsechlaimi gave them battle, in which Ualgarg Ua Ciardha, king of Cairbri, and Tadhg Ua Cearnachan, sub-king of Breifne, and many others, were killed by him”.                                                                                (from “The War of the Gaedhil with the Gaill”, Translation from the Irish – by - James Todd, 1867)

Then, again in the Kingdom of Meath, in 1030 -                                                                                                                                                                          “a battle was gained by the Gott, i.e., Domhnall, wherein fell Ua Cearnachain, Lord of Luighne”.*                                                                 (from “The Annals of the Kingdom of Ireland by the Four Masters” -  Completed in 1636, and translated from the original Irish by John O’Donovan, 1854).                  

However, earlier records of patronymic CEARNACHAN associated with the Barony of Luighne take us back to 896AD when                                                 “a rival was killed by the Luighne i.e. by the sons of Cearnachan”                                                                                           (ibid – O’Donovan)  


From these citings, we can speculate about the identity of that CEARNACHAN who was the family’s eponymous ancestor; also accepting that the Tadhg Ua Cearnachain who fell in battle in 1012 (see above) was most likely the first of the line to carry the surname. Perhaps that illustrious eponymous ancestor was the CEARNACHAN, King of Breifne**, who died in 931.

The last mention of UA CEARNACHAIN in The Annals of the Kingdom of Ireland was in 1159, once again concerning a battle in Meath, wherein he was listed as one of the prominent defeated                                                     “these were the Chieftains slain of the Ui-Briuin : Mac-na-haidhche Ua Cearnachain” 

  The following is a translated extract from “A Topographical and Historical Poem” by John O'Dubhagain, who died in 1372


Look over Luighne* of the full lakes,

Make a commemoration of the Ui-CEARNACHAIN

Good is every habitation of that people;

O'Gadhra is of that fine race.

* Luighne,..... a Barony in the then Southern O'Neill's Kingdom of Tara. The Barony is now spelt LUNE and is in the western part of modern County Meath, in the Province of Leinster. It comprises 4 parishes, the largest of which is Killaconnighan.

** Breifne.......An ancient Kingdom composed of a Confederation of Petty Kingdoms spread over the present day counties of Cavan, Meath, Westmeath and Longford, The Hill of Tara, the seat of the High King, is situated in the centre of County Meath and was under the protection of the King of Breifne. It was fully dissolved by mid-13th Century



  Patrick Woulfe in “Irish Names and Surnames” ,1923  - has the following notation for the surname -                                                                           

   O CEARNACHAIN – “the name (1) of a Meath family who were anciently chiefs of Luighne; and                                                                                                                                      (2) of a Tirconnell family who were the chiefs of Tuath Bladhach (now angl. Doe) in the barony of Kilmacrenan”

Medieval TIRCONNELL is now County Donegal and it was from that county that many of us believed our Irish KERNAGHANs originated from. Kilmacrenan, at the very north of Co Donegal, is quite a distance from the Kingdoms of Meath and Breifne of the UA CEARNACHAINs (from whence that surname has now been part of the living language of Ireland for over 1,000 years).

 In the ancient texts, the first we hear of the O CEARNACHAIN Clan in DONEGAL was in the 12th Century, and this again is in “A Topographical and Historical Poem” by John O'Dubhagain, (d. 1372AD)

 To MacGillatsamhais the stout,

Belong Ros-GuiU and Ros-Iorguil

Two other chieftains, it is certain to you,

Are over the victorious Tuath-Bladhach.

Of them is O'CEARNACHAIN of valour

Some of whose prosperities I have proved.

Of them is the royal host of prosperous tribes,

The bountiful Muintir Dalachain*   


 *  Under a “List of Irish Clans”, the entry for Muintir Dalachain (the lands of Dalachain*) has -  

        "Hereditary Chief or Clan chief;      Ó CEARNACHAIN (i.e. Kernaghan) and Ó Dalachain                                                                               

      Location;            Tuath Bladhach (Bladhaigh) (now Creeslough & Dunfanaghy) plus south of Ros-Iorguil (now Downings and Carrigart) County Donegal"

(*These Dalachain lands are in the northeastern part of Co Donegal’s Barony of Kilmacrenan and were within the Kingdom of Tyrconnell, the Lords of which up to the 14th Century were the O’Donnell’s).


Separately, we can place our KERNAGHAN Clan in this part of Donegal to the 12th Century, per -      

“the following clans and chiefs in Tir Connail in the Twelfth Century are given....X. O’Çearnachain, or O’Kernaghan; and O’Dalachain, Chiefs of the Tuath Bladhaigh                                                                                                     From The Annals of the Kingdom of Ireland” translated from the original Irish of The Four Masters, and with commentary,  by Owen Connellan, 1845.


Additionally, “Baronies of Ireland” states for the Barony of Kilmacrenan that                                                                                                                  “Other medieval septs include O'Kernaghan of Clondavaddog*”,        

(*  That Parish, Clondavaddog, also in the Barony of Kilmacrenan, covers most of the peninsula of Fanad in the extreme north of Co Donegal and is adjacent to the south and west to where the lands of Dalachhain are).


Unfortunately, dating is not given for either of the references to Ó CEARNACHAIN in 'List of Irish Clans' – and – 'Baronies of Ireland'). Nevertheless, from Connellan’s text above, we can place the O’ÇEARNACHAINs in Tir Connail (modern Co. Donegal) to within a couple of centuries after their first mentions in Co. Meath but we don’t know if (and when) the Meath clan moved to Donegal after their defeat in 1159.

In the second half of the 14th century, however, most of the Barony of Kilmacrenan in Donegal was taken over by the MacSweeneys Clan who then settled their own people throughout the land, displacing many of the earlier inhabitants.


It is from this latter (Tir Connail) era that many of us believed our Irish KERNAGHANs had originated in County Donegal. However, even as early as 1665, when the Hearth Money Rolls were conducted in County Donegal, there were no KERNAGHANs (nor surname variants) recorded in that county. (However, in Donegal's 1665 Hearth Money Rolls there was a Townland called Ballim Kernaghan, located on the Island of Inch close to the O’Çearnachain's former lands. That Townland has since been re-named Carnaghan).

All the Kernaghans that were recorded in the extant Hearth Money Rolls from the 1660s were in County Antrim (and these were all spelt starting Carn...)Regrettably the Rolls for Counties Down and Armagh, the 2 other most populous Counties per the 1901 Census, no longer exist.

There were no Kernaghans etc in County Donegal per Griffiths Valuation of 1857, a comprehensive listing of all Householders in each County of Ireland and only 1 (a William Kernaghan of South Donegal) in the Tithe Applottment Books of 1834.

Finally, O'KERNAGHAN is listed twice under the Principal Ancient Celtic Families (together with the Counties in which they were located) in "A Topographical and Historical Map of Ancient Ireland by Baronies" by Phillip MacDermott, 1846, which covers Ireland from 1171 (the English Invasion). The first entry is for County Donegal in Ulster while the second is for County Sligo (which borders Co Donegal in the south but is in the Province of Connacht). The Map of Sligo has O'Kernaghan, C (indicating Chief) in the Barony of Leyny, however, there is no text attaching to the Map to support sourcing of this nor to indicate time-frame and we have no other evidence of O'Kernaghans in Co Sligo.  


The earliest Sources of Irish registers that contain actually list KERNAGHAN etc date back to the first half of the 17th Century. The Muster Roll of 1630 included a John Carnahan of Belfast, Co Antrim noting he had "no Armes" (ie no weapons). 

Other Sources from the 17th and 18th Centuries that contain KERNAGHAN etc are the Hearth Money Rolls of 1660s,  the 1740 Protestant Householders Returns and the Flaxgrowers' Bounty List of 1796.                                     

Click Here for details of the individual Kernaghans etc that are  listed on these returns.

In relation to my own KERNAGHANs in Co Antrim, they are first recorded in 1669 on the Hearth Money Roll for the Parish of Connor, in the Barony of Antrim Lower. 

Here  were listed a JAMES CARNEKAN and an ALEXANDER CARNEKAN , both in the Townland of "fFurnisky" (Fernisky) which is adjacent to Artnagullian where my Kernaghan ancestors can be traced to in the 19th Century. Coincidentally, on my Kernaghan ancestral line, the first born sons are alternatively named James and Alexander. 

Within the townland of Artnagullian are 2 sub-townlands, one of which is KERNAHANSTOWN, likely denoting a substantial farm property but whose origin I have been unable to identify.

Close to the Parish of Connor in mid-Antrim is that of Duneane which has a townland called Aghacarnaghan, derived from the Irish: Achadh Cearnachain, meaning Kernaghan's field.

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