Top 100 Irish last names explained

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

(O) Malley - Mailey  Ó Máille. (meall, peasant). A branch of the Cenél Eoghain located in Tyrone where their territory was known as ‘O’Mellan’s Country’. They were hereditary keepers of the Bell of St. Patrick.

O’Meara - Mara  Ó Meadhra (meadhar, merry). This well-known sept, which has produced many distinguished men and women, gave its name to the village of Toomevara, which locates their homeland. This one of the few O names from which the prefix was never very widely dropped.

Molloy - Mulloy  Ó Maolmmhuaidh. (The adjective muadh) denotes bit and soft as well noble). An important sept of Fercal in mid-Leister. Molly is an anglicized form of Ó Maolaoidh. Apart from five variant spellings, such as Maloy and Mulloy, Molloy has been officially recorded as synonym of Mulvogue (Connacht), Logue (Co. Donegal), Mullock (Offaly), Mulvihill (Kerry), and Slowey (Co. Monaghan) while Maloy has been used for MacCloy in Co. Derry.

(O) Moran - Apart from MacMorran of Fermanagh, which has inevitably been changed to Moran, there are a number of distinct septs of Ó Moráin and Ó Moghrain whose name is anglicized Moran. Four of these are of Connacht-in which province the name is much more numerous  than elsewhere-originally located (a) at Elphin (akin to the O’Connors), (b) in Co. Leitrim (of the Muinitir Eolais), (c) in. Co. Mayo at Ardanee, (d) in Co. Galway, a minor branch of the Uí Maine. The Leitrim families are also called Morahan, as is the fifth to be enumerated, viz. that of Offaly, where Morrin is a synonym.

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.

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