The top 100 Irish last names explained

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Hanlon - Ó hAluain (possibly from luan, champion, intensified by an) One of the most important of the septs of Ulster. The present association of the name with West Munster is of comparatively recent inception.

O'Hara - Ó hEaghra. An important dual sept located in Co. Sligo, the chiefs being O’Hara Boy (buidhe) and O’Hara Reagh (riabhach). A branch migrated to the glens of Antrim.

(O) Healy - Hely  This is Ó hÉalaighthe in Munster, sometimes anglicized Healihy, and ÓhÉilidhe in north Connacht, derived respectfully from words meaning ingenious and claimant. Ballyhelyon Lough Arrow was the seat of the altar. The Munster sept was located in Donoughmore, Co. Cork, whence was taken the title conferred on the Protestant branch.

(O) Heaney - Heeney T he Principal sept of this name is Ó hÉighnigh in Irish, important and widespread in Oriel, formerly stretching its influence into Fermanagh. Hegney is a variant. Another family of the name Ulster were erenaghs of Banagher in Co. Derry. Minor septs of Ó hÉanna (Éanna, old form of Enda), also anglicized Heaney, were of some note in Clare, Limerick, and Mayo up to the seventeenth century.

(O) Higgins - Ó hUigín (from an Old-Irish word akin to Viking, not from uige). A sept of the southern Uí Néill which migrated to Connacht. The O’Higgins father and son of South American fame came from Ballinary, Co. Sligo, not Ballina.

(O) Hogan - Ó hÓgain (og, young) Three septs are so called: one is Dalcassian and one of Lower Dormond (sometimes regarded as the same); there is also one of the Corca Laoidhe.

Kane - O Cahan  Ó Catháin. As lords of Keenaght the O’Kanes were a leading sept in Ulster up to the time of the plantation of Ulster. The name is still very numerous in its original homeland.

Keating - One of the earliest Hibernicized Anglo-Norman families whose name was gaelicized Ćeitinn. They settled in south Leinster. The historian Dr. Geoffrey Keating was of C. Tipperary. The name with the prefix Mac is associated exclusively with the Downpatrick area, where MacKetian is a synonym of it. The theory that Keating is derived from  Mac Eitienne  is improbable. Woulfe makes it toponymic. The most acceptable suggestion is that it is from Cethyn, a Welsh personal name.

(O) Kelly - Ó Ceallaigh (The derivation of Kelly is uncertain: the most probable suggestion is that is from ceallach, strife) The most important and numerous sept of this name is that of the Uí Maine. Kelly is the second most numerous name in Ireland. In 1890 less than one percent of them had the prefix O but this has been to some extent resumed.

Mac Kenna - Kennagh  Mac Cionaoith. A branch of the southern Uí Neill, mainly located in Co. Monaghan where they were lords of Truagh; the name is now fairly numerous also in Leinster and Munster. Locally in Clare and Kelly the last syllable is stressed, giving the variants Kennaw, Ginna, Gna, etc.

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