The top 100 Irish last names explained

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

Moynihan - Ó Muimhneacháin (Muimhneach, Munsterman). Although there was a small sept of this name, sometimes changed to Munster, in Mayo, families so called belong almost exclusively to south-west Munster, Moynihan being very numerous on the borders of two counties. Minihan, another form of the name, is mainly found in Cork.

(O) Mulligan - Ó Maolagáin (probably a diminutive of maol, see MacMullen). An important sept in Donegal, much reduced at the time of the Plantation of Ulster and now found more in Co. Mayo and Monaghan.

(O) Murphy - Ó Murchadh. Murphy is the most numerous name in Ireland. The resumption of the prefixes O and Mac, which is a modern tendency with most Gaelic-Irish names, has not taken place in the case of Murphy.

(Mac) Nally - Mac Anally Mac an Fhailghih (failgheach, poor man). Without the prefix Mac this name now is found mainly in Mayo and Roscommon; with the Mac it belongs to Oriel. Woulfe says that the Mayo Nallys are of Norman or Welsh oigin and acquired a Gaelic name. This is unlikely in the case of the MacNallys of Ulster as there they are often called Mac Con Ulaidh (son of the hound of Ulidia, i.e. eastern Ulster). In the ‘census ‘ of 1659 it appears as MacAnully, MacEnolly, MacNally, and Knally, all in Oriel or in counties adjacent thereto.

Mac Namara - Mac Conmara (hound of the sea). The most important sept of the Dál gCais after the O’Briens to whom they were marshals.

(O) Nolan - Knowlan Ó Nualláin (nuall, shout) In early times holding hereditary office under the Kings of Leinster, the chief of this sept was known as Prince of the Foherta, i.e. the Barony of Forth, in the present county of Carlow where the name was and still is numerous. A branch migrated to east Connacht and Co. Longford, in Roscommon and Mayo Nolan is used synonymously with Holohan (from the genitive plural); and in Fermanagh as an Anglicized form of ÓhUltacháin (Hultaghan). There was also a sept of the name of Corca Laoidhe which is now well represented in Co. Kerry.

Prendergast - de Priondragás. One of the powerful families which came to Ireland at the time of the Anglo-Norman invasion. They are still found mainly in the places of their original settlement. Some of those in Mayo assumed the name FitzMaurice.

MacQuaid - Quade  Mac Uaid (son of Wat). A well-known name in Co. Monaghan and adjacent areas. Without the prefix Mac the name is found in Co. Limerick.

(O) Rafferty - Ó Raithbheartaigh, mod. Ó Raifeartaigh. Though etymologically this (from rath bheartach, prosperity wielder) is distinct from Ó Robhartaigh (from robharta, full tide) anglicized O’Roarty, these two names have been treated as one, at least since the fifteenth century. As co-arbs of St. Columcille on Tory Island Roarty is now mainly Co. Donegal while Rafferty is of Co. Tyrone and Co. Lough.

(O) Rahilly - Ó Raithile this well-known Munster family originated as a branch of the Cenél Eoghain in Ulster buthas long been closely associated with west Munster, the poet Egan O’Rahilly for example was a Kerryman.

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