The top 100 Irish last names explained

Find out more about your Irish roots and where your family name hails from

O’Brien - Ó Briain. A Dalcassian sept, deriving its name from historical importance from the family of King Brian Boru. Now very numerous in other provinces as well as Munster, being the fifth most numerous name in Ireland. In some cases O’Brien has been made a synonym of O’Byrne and others of the Norman Bryan.

Browne - De Brún, more correctly le  Brún (brown). One of the Tribes of Galway. Other important families of Browne were established in Ireland from the Anglo-Norman invasion onwards. The Browns of Killarney, who came in the sixteenth century, intermarried with the leading Irish families and were noted for their survival as extensive Catholic landowners throughout the period of the Penal Laws (The Kenmare associated with their name is in Co. Limerick) The Browne family shown on the map in Co. Limerick is of Camus and of earlier introduction. Yet another important family of the name was of the Neale, Co. Mayo. In that county Browne has also been used as a synonym of (O) Bruen.

Burk - de Burgh  de Búrca. This one of the most important and most numerous Hiberno-Norman names. First identified with Connacht it is now numerous in all the provinces (least in Ulster). Many sub-septs of it were formed called MacHugo, MacGibbon, Mac Seoinín (Jennings), MacRedmond, etc.

Butler - Always called deBuitléir in Irish, though it is of course properly le Butler not de. It is one of the great Norman-Anglo which, however, did not soon become hibernicized like the Burkes, etc. Historically it is mainly identified with the Ormond country. It is now very numerous in all the provinces except Ulster.

MacCabe -  Mac Cába. A galloglass family with the O’Reillys and the O’Rourkes which became a recognized Breffny sept. Woulfe suggests cába, cape, a surname of the nickname. Having regards to their origin it is more likely to be from a non-Gaelic personal name.

Callaghan -  Ó Ceallacháin The derivation from ceallach, strife, which usually given, is questioned but no acceptable alternative has been suggested. The eponymous ancestor in this case was Ceallacháin, King of Munster (d. 952). The sept was important in the present Co. Cork until the seventeenth century and the name is still very numerous there. The chief family was transplanted under the Cromwellian regime to east Clare, where the village of O’Callghan’s Mills is called after them.

Campbell - Mac Cathmhaoil (cathmhaoil, battle chief). An Irish sept in Tyrone; in Donegal it is usually of Scottish galloglass origin, viz. Mac Ailín a branch of the clan Campbell (whose name is from cam béal, crooked mouth) Many Campbells are of more recent Scottish immigrants. See MacCawell. The name has been abbreviated to Camp and even Kemp in Co. Cavan.

MacCarthy - Mac Ćarthaigh (cárthach, loving). The chief family of the Eoghanacht and one of the leading septs of Munster, prominent in the history of Ireland from the earliest times to the present. MacCarthy is the most numerous Mac name in Ireland.

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