O'Neill Last Name: Meaning and Origin

This surname, which is one of the very few to have retained not only the O prefix but also the Gaelic spelling, is among the ten most numerous in Ireland, and one of the most famous and prominent in the history of Ireland. It is among the first ten names in Counties Antrim, Derry and Tyrone.

The O’Neill sept trace their lineage to Eogan, son of the 5^th century High King of Ireland, Niall of the Nine Hostages, who ruled from the Hill of Tara, County Meath. Eogan and his brother Conall Gulban conquered northwest Ireland, ca.425 AD, capturing the great hill-fort of Grianan of Ailech in County Donegal.

Grianan of Ailech

Where Does the Last Name O’Neill Come From?

Eogan, styled ‘King of Ailech’, established his own kingdom in the peninsula in County Donegal still called after him Inishowen (Innis Eoghain or Eogan’s Isle). His descendants, known as the Cenel Eoghain (the race of Owen), became the principal branch of the Northern Ui Neill (descendants of Niall of the Nine Hostages). The Cenel Eoghain in the next five centuries expanded to the east and south from their focal point in Inishowen.

Inishowen

Ireland was one of the first countries to adopt a system of hereditary surnames which developed from a more ancient system of clan or sept names. The surname was formed by prefixing either Mac (son of) or O (grandson or descendant of) to the ancestor’s name.

The first to take O’Neill as their surname was Domhnall who took the name of his grandfather, Niall, Black Knee, High King of Ireland who was killed in a battle with the Vikings in 919 AD. The O’Neills were thus in Gaelic O Neill i.e. grandson of Niall.  In the middle years of the 11^th century the O’Neills moved their capital from Ailech to Tullaghoge (near Cookstown, County Tyrone).

After a decisive battle in 1241 at Caimeirge (which scholars believe was near Maghera in County Derry) the O’Neills ousted the McLaughlins as the senior branch of the Northern Ui Neill. Brian O’Neill was now ‘installed in the lordship of the Kinel-Owen’, his territory being Tir Eoghain (Tir Owen or Tyrone, the land of Owen) which extended over the present counties of Tyrone and Derry.  

Northern Ui Neill

The senior branch of this sept, the O’Neills of Tyrone, were frequently High Kings of Ireland, and in the 16^th and 17^th centuries they were the leaders of Gaelic resistance to English attempts to pacify Ireland. A junior branch established themselves in County Antrim in the 14^th century and from their seat at Shane’s Castle became known as the Clannaboy or Clandeboy O’Neills.

Shane's Castle

O'Neill Spelling Variations

The different spelling variations for this surname are: O'Neill, Neal, Neale, Neales, Neil, Nihill, Niell, O'Neil, O,Nail, O'Niel, O'Neal, Ó Neill, Ó Néill, Ua Néill and Uí Néill.

O’Neills Who Have Marked their Surname in History

The escape of the most prominent Gaelic Lords of Ulster, including Hugh O’Neill who was styled the ‘Prince of Ireland’, in ‘the Flight of the Earls’ in 1607 from Lough Swilly marked the end of Gaelic power and paved the way for the 17^th century Plantation of Ulster with English and Scottish settlers.

Hugh O'Neill; 2nd Earl of Tyrone

The flight of the Earls

In the 17^th and 18^th centuries many descendants of the old Gaelic order in Ireland emigrated, as the so-called Wild Geese, to Europe, and, in particular, to Spain and France. The European branches of the O’Neills distinguished themselves in the military of France, Spain and Portugal.

Alexander O'Neal; American musician and singer

Andrew O'Neill; British comedian, musician, presenter and writer

Arthur Edward Bruce O'Neill; Irish Ulster unionist party politician

Brian O'Neill; American ice hockey player

Christopher O'Neill; British-American businessman and husband of princess Madeleine of Sweden

Dan O'Neill; American underground cartoonist

Dick O'Neill; American stage, film and television actor

Ed O'Neill; American actor

Elizabeth O'Neill; Irish actress

 Eugene O'Neill; author and winner of Nobel prize for literature

Jennifer O'Neill; Brazalian-American actress and model 

James Anthony "Jimmy" O'Neill; Irish football goalkeeper 

Mary Devenport and Joseph O'Neill; Irish poet and author

Michelle O'Neill; Irish politician

Onora O'Neill; baroness O'Neill of Bengarve and British philosopher

Owen Roe O'Neill; Gaelic Irish soldier of the O'Neill dynasty of Ulster

Sir Neil O'Neill; second baronet of Shane's castle

Thomas Philip "Tip" O'Neill; American politician (on the right)

This surname history has been researched and written by Brian Mitchell. Brian has been involved in local, family and emigration research in Derry and North West Ireland since 1982. The database whose construction he supervised, containing one million records (dating from 1628 to 1930) extracted from the major civil and church registers of County Derry, can now be accessed at www.derry.rootsireland.ie. Brian can be contacted by email at genealogy@derrystrabane.com.