The surname Callaghan can be traced back to Ceallachán Caisil, the name of the formidable Chief of the Eóganachta tribe and King of Munster (in Ireland) from AD 935 until 954 who, amongst many other famed accomplishments, is said to have defeated the father of Brian Boru of the Dal gCais, in battle! Caellachán is thought to be a diminutive form of the Gaelic word Ceallach, the origin of which is unknown, but suggestions for its meaning(1) include bright-headed (as a personal name) or strife/war (in the sense of fight or contention for superiority). Ireland spent much of its life occupied by foreign powers that anglicised Irish names giving rise to many variants. Moreover, the lack of standardised spelling (the first dictionary, written by Robert Cawdrey, wasn’t published until 1604!) meant the process of converting what may be identical oral sounds into written words also generated numerous variations. Added to this, Irish names contain many prefixes(2) and silent letters that clerks of occupying powers, or those involved in immigration procedures, would often drop somewhat randomly. These situations created multiple alternatives of surnames. In the case of Ceallachán this gave rise to versions such as Ceileacháin, Ceilahan, Callachan, Calachan, Ceilaghan, Ceallaghan, Cellachain, Cellachan, Cellaghan, Callaghan, O'Callaghan, Callahan, O'Callahan, Calahan, Callagan, Calagan, Callighan, Kalahan, Kallaghan, Kallahan, O'Kallaghan, Kellaghan, Kelleghan, Kellahan, Kelahan, Keelaghan, Kealahan & Keelan. Some variants of names can be related to particular septs as, for example, Ó Ceileacháin is especially popular with septs found in the Irish counties of Armagh, Louth, Meath and Monaghan whereas, in Munster (Clare, Cork, Kerry, Limerick, Tipperary & Waterford), Ceallachán is favoured over Ceileacháin (perhaps because of the direct mapping of the name to the ancient king, although some argue the spoken sound of Ceallachán better matches the variants of 'Callaghan' found in Munster). The most widespread anglicised version is, perhaps, Callaghan with the first written record of that particular spelling being held in the Birth Records of County Cork, dated 1605, for one John O' Callaghan. In the 2011 census, the total number of people bearing either the name O'Callaghan or Callaghan in Ireland was of the order 13,000 (not as large as you might imagine!), but it still placed the name in the top-40 of Irish surnames in use.  Older hereditary records(3) place the original location of the sept bearing the name Ceallachán as being in the barony of Kinlea, in County Cork, an area they lost during the Anglo-Norman conquest under Strongbow (12th century) causing them to relocate to the vicinity of Mallow in the North of the county (with their main strongholds being castles at Clonmeen and Dromaneen). Here they experienced some four centuries of dominance, enjoying many earlier Gaelic customs such as the creach or cattle-raid; one chief of the Callaghan family (Donncha O'Callaghan, 1537-1578) was reputed to have conducted more than two hundred raids across Ireland. They remained in Cork until the Cromwellian plantation period (and the Irish rebellion of 1641) where, following the final surrender of 1652, they lost their ancestral lands and were transported to East Clare (in the barony of Tulla, where the name of Clare village of "O'Callaghans Mills" remains in testament to that resettlement). In further testament to those troubled times, just prior to being forcibly evicted from their Cork lands, it is reported that at least seventeen Callaghan’s had been declared outlaws! 20,000 acres (of 24,000 acres) confiscated from the Callaghan’s were recorded as belonging to one Donncha O'Callaghan, making him the most important Callaghan at that time to be dispossessed of property. It seems that other members of the sept either remained as tenants of the newly-installed English owners or fled to Europe. Interestingly, the Dublin Genealogical Office (in 1994) supported Don Juan O'Callaghan of Tortosa, Spain, in his claim to be the closest modern male descendant of Donough O'Callaghan adding supporting evidence to the exodus of many Callaghan’s to Europe during the turbulent years (giving rise to the oddity that the surname Callaghan is a reasonably well known in Spain!). In more modern times the descendants of the Callaghan sept have joined the broader Irish diaspora, being found in almost every country of the world. Meanwhile, back home in Ireland, and in an interesting twist to the story(4), the 20th Century, saw a branch of the Callaghan family returning to live in the ancestral land they were evited from in the mid-fifteenth century!  Talking of miraculous things, apparently there was a Saint Callaghan, or Ceallachán, who was a monk at Clontibret (County Monaghan, Ireland) with a feast day of the 24th of September. Of course it needs to be remembered that many of these tales come from a very misty past, so they are not without contention (none more so than names). Therefore, it is not surprising that academics (and others) take positions based on arguments of sept history or Gaelic language/grammar but the reality is that, what truths that may have existed, are somewhat obscured by mists of history and so, in many respects, the legends and facts will probably always be inseparably intertwined but hopefully that will not diminish their value in our lives!

In terms of the Callaghan Coat-of-Arms, such adornments have a somewhat chequered history, sometimes having associations with occupying powers and specific strands of families. Thus, while what is often regarded as a coat-of-arms for all Callaghan's, in reality was associated with a particular sept. However, modern times have seen a more generous adoption by the wider Callaghan fraternity. In the case of the Callaghan coat-of-arms, the official description is “Argent in base a mount vert, on the dexter side a hurst of oak trees, therefrom issuant a wolf passant towards the sinister all proper”. According to one plausible explanation, the oak trees shown on the coat of arms, depict an oak forest that played a vital role in aiding the inauguration of Ceallachán as king (and were a backdrop to the scene), with the wolf being an Irish wolfhound, a royal animal. The dexter and sinister, are terms for right and left. Alternatively, (or maybe as well as) the druids (whose influences had left their mark) believed the oak tree was the most noble and ancient of trees forming a connection between the real and otherworld and so it had special meaning. The motto which is often attached is “Fidus et audax” (Faithful and bold) with bold being strong or determined. 

Finally, if you bear the name Callaghan, or perhaps have ancestors that bore the name somewhere in your family tree, then you are joined to a fraternity whose shared genes or spirit drive the dreams that make us who we are, and who we will be; while we may never meet, we are all part of a great adventure whose story is still unfolding :-)


The following web-links provide some information on people bearing the 'Callaghan' family name (including all its variants). If you would like to be included, or to include a deceased relative, please email an A4 description, preferably in Microsoft WORD format but other formats are acceptable (there is no cost). Include a minimum of: full name, date/place of birth/death, photo & summary of life (you don't need to be famous or have done special things to be included - both female and male lines are equally welcome). The ambition for this project is to provide a record (or memorial) to as many people bearing this family name (and all variants) as possible, hopefully one that will outlive all our mortal lives!

Some Examples:

·         Cellachán mac Buadacháin (Ceallachán Caisil)

·         Christopher David Callaghan

·         George Astley Callaghan

·         Leonard James Callaghan (Jim Callaghan)


(1)   Concerning the meaning of Callaghan, another view is that it was derived from 'cal-a-han' meaning "lover of churches" or  "frequenter of churches"

(2)   Prefixes to Irish names are formed as follows; Bean Uí means wife of, in a girl’s name means daughter of and ó means descended from (eg grandfather or earlier ancestor). Originally the most common form was O’Callaghan although the “O” was frequently dropped to simplify official record keeping (especially when immigrating to countries like the USA where clerks frequently dropped the “O” prefix to simplify filing).

(3)   Hereditary surnames are said to have been introduced to Ireland sometime after 1100. For example, in the case of the Callaghans, Murchadh Ua Ceallachán who lived in the early eleventh century, and a grandson of the original King Ceallachán, was the first to transit the surname hereditarily.

(4)   After the Ceallachán/Callaghan sept forfeited their Cork land it was taken over by the Longfield family who, in 1720, built a grand house on original Ceallachán/Callaghan land. Reinforcing the vigour of these changes, in 1795, Richard Longfield became Baron Longueville. However, in a twist of fate,'Longueville House' and land was returned to the Callaghans in 1938, when it was purchased (from the Longfields) by Senator William O'Callaghan whose son Michael and wife Jane opened it to the public in in 1969 as a simple Bed & Breakfast. More recently, their eldest son William, with his wife Aisling, now run it as a luxurious guesthouse, with William O'Callaghan acting as head chef in its highly acclaimed restaurant specialising in 'field-to-fork' food (food from its working farm). The family are direct descendants of Donough O'Callaghan who fought in 1640 rising. This surely was an amazing twist of fate that took these lands and the families concerned on an adventure through numerous generations that was beyond the wildest imagination of all but those harbour indestructible dreams and who never lose fate!


Useful Sources of Information:

·         Chris O'Callaghan “Book of The Callaghan“, 365 pages, Co. Cork, Ireland, 2014, ISBN: 978-0-9565354-2-9 - The first in-depth factual account of Ceallachán Caisil, the formidable Chief of the Eóganachta tribe and King of Munster during the period 934-954. The book details 6 years of research to reveal a successful and popular king whose legendary exploits have given him a special place in Irish history

·         Joseph F.O Callaghan, "Clan Callaghan: The O Callaghan Family of County Cork", 302 pages, publisher Genealogical.Com, Inc, published 23 Nov 2020 (revised edition), ISBN: 9780806359168, 2020 (revised) - A well-researched book that traces the O'Callaghans (and variants of the name) from their beginnings in Munster Ireland through the upheavals of history which have seen their progeny scattered around the world.

·         Wikipedia Entry - https://en.wikipedia.org/wiki/O'Callaghan

·         Edward MacLysaght, "Irish Family Their names, Arms and Origins", Irish Academic Press, 1957, 1982, 1991, ISBN 0-7165-2364-7

·         Longueville House – In case you are planning a visit to the Blackwater Valley, where the O'Callaghan clan lands were, this small hotel has is situated on property confiscated by Cromwell in 1650 but which returned to the O'Callaghans in 1938, when the Longfield family sold the property to Senator William O'Callaghan, and continues to be run by his descendants.


Last Updated:  29 July 2021