The top 100 Irish last names explained

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

(O) Dempsey -  Ó Díomasaigh (díomasach, proud). A powerful sept in Clanmalier. O’Dempsey was one of the very few chiefs who defeated Strongbow in a military engagement. Many of his successors distinguished themselves as Irish patriots and they were ruined as a result of their loyalty to James II. The name is now numerous in all the provinces.

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Disney -  Derived from a French place-name and originally written D’Isigny etc., the name Disney occurs quite frequently in the records of several Irish counties in the south and midlands since the first half of the seventeenth century.

(O) Dolan - The general accepted form in Irish today is Ó Dúbhláin (mod. Ó Dúláin) as given by Woulfe and others. O’Dolean, later Dolan, derives from Ó Dobhailen the name of a family on record since the twelfth century in the baronies of Clonmacnowen, Co. Galway, and Athlone, Co. Roscommon, in the heart of the Uí Mainecountry and quite distinct from Ó Doibhilin (Devlin). There has been a movement north-eastwards so that now the name Dolan is numerous in Co. Leitrim, Fermanagh, and Cavan as well Co. Galway and Roscommon.

Mac Donagh - Mac Donnchadha (son of Donagh). A branch of the MacDermots of Connacht where the name is very numerous. In Connemara the name is usually that of a branch of the O’Flahertys. The MacDonagh sept in Co. Cork were a branch of the McCarthys: the name is now rare there and apparently many of these resumed the name MacCarthy.

O’Donnell -  Ó Domhnaill. The main sept, one of the most famous in Irish history, especially in the seventeenth century, is of Tirconnell; another is of Thomond and a third of the Uí Maine.

(O) Donoghue - Donohoe  ÓDonnchadha. An important sept in Desmond: where the name was perpetuated in the territory called Onaght O’Donoghue. There also were two others in County Galway and Co. Cavan where the spelling Donohoe is usual. According to Dr. John Ryan there was another O’Donoghue sept in Co. Tipperary of Eoghanacht. Descent.

Mac Dowell - Mac Dubhghaill (dubh, black-gall, foreigner) This is the Irish from of the name of the Scottish family of Macdugall which came from the Hebrides of galloglasses, and settled in Co. Roscommon where Lismacdowell locates them. It is now mainly found in north Ulster, largely due to more recent immigration.

(O) Duffy - ÓDubhthaigh. *A numerous name in all the provinces except Munster. Modern statistics show that is now the most numerous name in Co. Monaghan.

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