Ireland was one of the first countries to adopt hereditary surnames, many of which were devised during the reign of Brian Boru, the High King of Ireland, who fell defending Ireland from the Vikings at the Battle of Clontarf in 1014AD. Many of these names began as patronyms to define a son from his father or grandson from his grandfather. Thus, the reason for the common prefixes found on Irish surnames. Mac, sometimes written Mc, is the Gaelic word for "son" and was attached to the father's name or trade. O is a word all by itself, signifying "grandson" when attached to a grandfather's name or trade. The apostrophe that usually follows the O actually comes from a misunderstanding by English-speaking clerks in Elizabethan time, who interpreted it as a form of the word "of." Another common Irish prefix, Fritz, derives from the French word fils, also meaning "son."
Does your family carry one of these 50 common Irish surnames?
This Irish family was very widespread, settling in Fermanagh, Galway, Kerry, Kilkenny, and Westmeath. They are now mostly found in County Sligo and the province of Leinster.
Brown or Browne
Common in both England and Ireland, the Irish Brown families are most commonly found in the province of Connacht (specifically Galway and Mayo), as well as Kerry.
The O Boyles were chieftains in Donegal, ruling west Ulster with the O Donnells and the O Doughertys. Boyles can also be found in Kildare and Offaly.
This Norman name originated from the borough of Caen in Normandy (de burg means "of the borough." )The Burkes have been in Ireland since the 12th-century, settling mainly in the province of Connacht.
The O Byrne (Ó Broin) family originally came from Kildare until the Anglo-Normans arrived and they were driven south to the Wicklow mountains. The Byrne surname is still very common in Wicklow, as well as Dublin and Louth.
The Callaghans were a powerful family in the province of Munster, and most numerous in Clare and Cork.
Campbell families are very prevalent in Donegal (most are descended from Scottish mercenary soldiers) as well as in Cavan.
The O Carroll surname can be found throughout Ireland, including Armagh, Down, Fermanagh, Kerry, Kilkenny, Leitrim, Louth, Monaghan, and Offaly. There is also a MacCarroll family (anglized to MacCarvill) from the province of Ulster.
One of the oldest surnames in Ireland, the O Clery surname (anglicized to Clarke) is most prevalent in Cavan.
The Irish Collins surname originated in Limerick, though after the Norman invasion they fled to Cork. There are also Collin families from the province of Ulster, most of whom were probably English.
Three distinct O Connell clans, located in the provinces of Connacht, Ulster, and Munster, are the originators of many of the Connell families in Clare, Galway, Kerry.
Originally an Irish clan from Galway, the Connolly families settled in Cork, Meath, and Monaghan.
In Irish Ó Conchobhair or Ó Conchúir, the name means hero or champion. The O Connors were one of three royal Irish families; they are from Clare, Derry, Galway, Kerry, Offaly, Roscommon, Sligo and the province of Ulster.
The Irish Ó Dálaigh comes from dáil, meaning a place of assembly. Dalys hail from Clare, Cork, Galway and Westmeath.
The name in Irish (Ó Dochartaigh) means obstructive or hurtful. In the 4th century the Dohertys settled around the Inishowen peninsula in Donegal, where they've primarily stayed. Their surname is the most common in Derry.
The name comes from dubh ghall, the "dark foreigner," and is thought to be Norse in origin. In the province of Ulster they were known as Mac Dubghaill (MacDowell and MacDuggall). The greatest concentration of Doyles is in Leinster, Roscommon, Wexford and Wicklow.
Ó Dubhthaigh comes from an Irish name meaning black or swarthy. Their original homeland was Monaghan, where their surname is still the most common; they are also from Donegal and Roscommon.
From the Irish for brown (donn), the original Irish name Ó Duinn has by now lost the O prefix; in the province of Ulster the final e is omitted. Dunne is the most common surname in LAois, where they originated.
The O Farrell chieftains were lords of Annaly near Longford and Westmeath.
A Norman family who came to Ireland in 1170, the Fitzgeralds (spelled Mac Gearailt in Ireland) claimed vast holdings in Cork, Kerry, Kildare, and Limerick.
The Irish surname Ó Floinn is prevalent in the province of Ulster, however, the f is no longer pronounced and the name is now Loinn or Lynn. Flynn families can also be found in Clare, Cork, Kerry, and Roscommon.
The Gallagher clan has been in Donegal since the 4th century and is the most common surname in this area.
Next Page > Irish Surnames H-Z