O'Donnell is an Irish surname from Ó Domhnaill, meaning “descendant of Domhnall.” The best-known historical line was the O'Donnell dynasty of Tír Chonaill in north-west Ireland, centered in what is now County Donegal. Surname scholar Patrick Woulfe also recorded separate Ó Domhnaill families in Clare, Galway, Carlow and Ulster. If you are shopping rather than researching, you can browse O'Donnell Irish family gifts here.
Quick answer: the O'Donnell name belongs above all to Donegal, because the Tír Chonaill dynasty became one of the major Gaelic powers of the north-west.
What does the O'Donnell surname mean?
The Irish form is Ó Domhnaill, literally “descendant of Domhnall.” Woulfe lists O'Donnell alongside historical record forms such as O Donill, O Daniell and Donnell. Those spellings are useful genealogy clues, because the O' prefix was widely dropped in English-language records and restored by many families from the late nineteenth century onward.
Why is O'Donnell so strongly connected with County Donegal?
The best-known Ó Domhnaill line belonged to the Gaelic political world of Tír Chonaill. Woulfe describes this family as descended in tradition from Conall Gulban and notes that it became the ruling family of Tír Chonaill after earlier local ruling families declined. The dynasty is also known as Clann Dálaigh in historical sources.
Members of this line held power across much of the north-west for centuries. Dictionary of Irish Biography entries document successive O'Donnell rulers of Tír Chonaill, including fifteenth-century Aodh Ruadh and later Red Hugh O'Donnell. Donegal Castle became one of the dynasty's most important seats, while the wider lordship included a network of allied and subordinate families across the region.
Were all O'Donnells part of the Tír Chonaill dynasty?
The Tír Chonaill line is the most famous, and Woulfe records five further Ó Domhnaill families: the lords of Corcabaskin in west Clare, who ruled there until the MacMahons displaced them early in the fourteenth century, chiefs in Uí Maine in County Galway, the lords of Idrone in County Carlow, a sept of Cinel Binnigh within the Cinel Eoghain, and a family of Uí Eathach in the Armagh area.
County Donegal is the heartland of O'Donnell history, and Woulfe, citing O'Donovan, traces the O'Donnells of Limerick and Tipperary to Shane Luirg, son of Turlough of the Wine, lord of Tír Chonaill in the early fifteenth century. A family's parish and townland records point to its branch.
Who was Red Hugh O'Donnell?
Red Hugh O'Donnell — Aodh Ruadh Ó Domhnaill, c.1572–1602 — was a leader of the Tír Chonaill dynasty during the Nine Years' War. The Dictionary of Irish Biography records him as the son of the ruling lord of Tyrconnell and describes his rise within the late sixteenth-century struggle in Ulster. His escape from captivity in Dublin and his alliance with Hugh O'Neill made him one of the best-known figures associated with the O'Donnell name.
After the defeat of the Gaelic alliance at Kinsale, Red Hugh traveled to Spain and died in 1602. In 1607 his brother Rory O'Donnell, Earl of Tyrconnell, departed Ireland with Hugh O'Neill and others in the event remembered as the Flight of the Earls. That episode marked the end of the old Tír Chonaill lordship's political position and a turning point in Ulster history.
How can I research an O'Donnell family line?
Start with the most recent known relatives and work backwards through civil records, church records, census returns, wills, land records and local place names. Record the spelling used in each source, including whether the O' prefix appears. For Donegal and other Ulster families, county, parish and townland information is especially valuable, because O'Donnells were numerous right across the province.
- 1901 and 1911 Irish census: use the National Archives of Ireland to locate households by surname and place.
- Civil and church records: IrishGenealogy.ie is a strong starting point for births, marriages, deaths and selected church registers.
- Ulster research: PRONI can be useful when a family crossed county or later jurisdictional boundaries in the north.
- Heraldry: the Office of the Chief Herald at the National Library of Ireland holds heraldic records and genealogical manuscripts for Gaelic families.
Frequently asked questions about O'Donnell
Is O'Donnell an Irish surname?
Yes. O'Donnell is an anglicized form of the Irish Ó Domhnaill, “descendant of Domhnall.”
Which counties is O'Donnell most associated with?
Donegal above all, as the home of the Tír Chonaill dynasty. Woulfe found O'Donnells numerous across Ulster and Munster, with historic families also in Clare, Galway, Carlow and Armagh.
Who are the most famous O'Donnells?
Red Hugh O'Donnell and his brother Rory, Earl of Tyrconnell, are the best known. Woulfe also highlights Leopold O'Donnell, prime minister of Spain and Duke of Tetuan, one of many O'Donnells who served continental powers.