A History of Irish Surnames | Irish Surname Origins

The Fascinating Origins of Irish Surnames

Irish surnames in a calligraphy book

Every Irish person has wondered about the meaning of their surname at least once. Read on to find out about your own Irish ancestry.

The history and meaning behind the most common Irish surnames

Few Irish surnames were fixed before the 10th century: people often took their father or grandfather’s surname, meaning surnames changed from generation to generation. Surnames could also be derived from occupations (such as Driscoll, meaning ‘messenger’), origin (such as Walsh, meaning ‘Welsh’), and even a person’s looks (Duff, for example, means ‘dark’). They could also be derived from epithets, such as Horan, which means ‘Warlike one’.

In the 1100’s, wealthy families started taking on hereditary surnames, which were passed on through the father’s line but did not change from parents to children. It wasn’t until the 16th century, however, that this custom became widespread.

Many surnames became anglicised, losing the Mc and O’ prefixes or being literally translated: Gabhann, for example, became Smith. Nowadays, thanks to several waves of migration over the 19th and 20th centuries, people all over the English-speaking world have Irish ancestry.


Crest of the Murphys of Wexford: a lion on a helmet over a shield depicting a lion and a tree

Pronunciation: Ó Murchú Oh Mur-ku

The most common surname in Ireland, Murphy, comes from Murchadh, a first name which came to mean “sea warrior”. (from muir, meaning sea, and cath, meaning battle). Murphy is an anglicised version of both MacMurchadh (son of Murchadh) and O’Murchadh (descendant of Murchadh). One branch of the powerful dynasty Cenél nEógain carried the surname MacMurchadh. They were native to Ulster.

The Murphy motto is ‘Vincere vel mori’, Victory or Death.

Perhaps the best-known Irish Murphy of our times is the comedian and actor Cillian Murphy.


Kelly family crest: a crown with a dog on it over a helmet on top of a shield depicting two lions flanking a castle tower

Pronunciation: Ó Ceallaigh Oh Kall-ig

In Irish, Ceallagh is a personal name, the meaning of which is disputed. Some say it means ‘bright haired’, others that it means ‘troublesome’, and yet others that it refers to someone who went to church often. Kelly is derived from O’Ceallagh (son of Ceallagh). Contrary to other surnames, Kellys do not have a single, famous ancestor. However, Kellys did form a powerful clan in Ui Maine, and another one in Breagh, which was a rival in strength until the Norman invasion.

Their motto is ‘Turis fortis mihi Deus’, or ‘God is my Tower’.

One notable Kelly was Grace Kelly, daughter of the Irish-American John Kelly. She was an actress who starred in such notable films as Dial M for Murder, and eventually married into the royal family of Monaco.


O’Sullivan crest: a helmet on top of a shield depicting two red creatures, a yellow stag and a black and white boar

Pronunciation: Ó Súilleabháin Oh Sool-a-wa-n

O’Sullivans are descendants of Fíngen mac Áedo Duib, king of either Cashel or Munster in the 7th century. They were originally part of the Eoganachta (or ‘Children of Owen’) dynasty. By 700-900AD, the Eogánacht had split into two factions, one of which took the name O’Suileabhain. This is another name whose meaning is unclear, but historians believe it means ‘one-eyed’ or ‘hawk-eyed’. O’Sullivans could originally be found in County Tipperary, but today they are concentrated in the counties of Cork and Kerry.

The O’Sullivan motto is ‘The steady hand to victory’.


Walsh family crest: a swan standing on a helmet over a red, black and white shield

As mentioned above, Walsh comes from Welsh – specifically, from the Norman Le Waleys. The Norman invasions of the 12th century saw not only Normans, but also Anglo-saxons and Welsh people settling in Ireland.

Their motto is ‘Pierced but not dead’, or ‘Do not irritate the lions’.


O’Brien family crest: a shield depicting three lions on a red background
Pronunciation: O’Briain Oh Bree-an

O’Briens have a rich heritage – they claim descent from a High King of Ireland, Brian Boru, who lived in the early 11th century. Brian Boru was considered the first ruler of all Ireland, although he perished in the very battle where he subdued the last of his enemies, the Norsemen. His descendants ruled over Munster, although their kingdom gradually shrank to encompass only the Kingdom of Thomond, which they ruled over until the 16th century.

The name Briain means ‘exalted one’, or ‘eminence’. O’Briens are nowadays still mostly found in areas formerly inhabited by O’Brien septs, such as counties Clare, Limerick, Waterford and Tipperary.

Their motto is ‘Lámh laidir an uachtar’, or ‘the strong hand from above’.

One successful O’Brien is Conan O’Brien, host of The Tonight show between 2009 and 2010.


Byrne crest: a mermaid on top of a helmet over a shield depicting three white hands on a red background

Pronunciation: Ó Broin Oh Broh-n

Another surname that derives from an ancient lineage is Byrne. Byrnes are descended from a 10th century king, Bran mac Máelmórd. He was the ancestor of the Ó Broin clan, who originally lived in the Kildare plains, and later expanded towards what is known today as Wicklow, where the surname is still quite common. There is a series of poems from the 16th century that collect the history of this clan: the “Book of the O’ Broin” (“Leabhar Branach”).

Their family motto is ‘certavi et vici’, ‘I have fought and conquered’.

Less commonly, Byrne can come from the Irish Ó Beirn. Ó Beirns can nowadays be found in Mayo, Sligo and Donegal.

Little-known fact: Hozier, the Irish singer and songwriter most known for his hit single ‘Take Me to Church”, is actually a Byrne; his full name is Andrew Hozier-Byrne.

Irish singer and songwriter Hozier, who has a common Irish surname


Ryan coat of arms: a griffin on top of a helmet over a red shield depicting three griffin’s heads

Pronunciation: Ó Riain Oh Ree-an

Ryan is the anglicised version of several different family names. It can come from the Irish Ó Riagháin, which means ‘descendant of Rían’; Ó Maoilriain, meaning ‘son of Maoilriaghain’, or Ó Ruaidhín, ‘son of the little red one’. The first name Rían is thought to mean ‘little king’ (from righ, meaning king, and the diminutive an).

The Ryan motto is ‘Malo Mori quam Foedari’, ‘Death before Dishonour’.

The surname Ryan might call to mind a number of celebrities, of which Meg Ryan is a prominent one. However, this actress is not a ‘real’ Ryan – the surname is only part of her stage name. Her real name is Margaret Mary Emily Anne Hyra.


O’Connor Kerry crest: an arm holding a sword over a helmet, on top of a green shield depicting a yellow creature

Pronunciation: Ó Conchubhair/ Ó Conċuḃair Oh Kon-ku-bar

The name Conchubhair was supposedly first used by Conchobar mac Taidg Mór, King of Ulster. O’Connors are descended from another Conchubhair, who ruled Connacht in the 10th century. There is no consensus about the meaning of this name, but the main theories are that it comes from the Irish for ‘lover of hounds’, ‘wolf-lover’ or ‘patron of warriors’. The Conchobair clan were renowned in Ancient Ireland: about a hundred Kings of Connacht and two High Kings of Ireland belonged to this clan.

The family motto is ‘Nec Timeo, Nec Sperno’ ; ‘I neither Fear nor Despise’.

The O’Connors are another clan boasting artistically inclined members, most notably Irish iconic writer Frank O’Connor.


O’Neill family crest, two lions flanking a hand on top of a fish

Pronunciation: Ua Néill Oh-Neel

O’Neills are said to have a common ancestor, Niall Glúndub, a 10th century High King of Ireland from the Cenél nEógain dynasty. His name was used as a surname by his descendants, a few generations later. O’Neills originally lived in Counties Tyrone and Clare.

Their motto is ‘Lám Dearg Éirinn’, or ‘The Red Hand of Ireland’

Nowadays there are famous O’Neills in everything from literature (Seamus O’Neill is a notable example) to sports (like the basketball player Shaquille O’Neill).


O’Reillys are descended from a group of families (Irish: Ó Raghallaigh) who ruled over East Bréifne (modern-day County Cavan, where most O’Reillys can be found today) and extended their territory into Westmeath. The clan were related to the O’Connors and the Ó Ruairc (O’Rourkes) of West Bréifne. O’Reilly is the tenth most common Irish surname, and it can be found in the Province of Leinster, Fermanagh, Westmeath, Longford, Monaghan, Meath
It is also the patronymic form of the Irish name Reilly (Irish Gaelic: Uí Raghaile).

Their motto is ‘With Fortitude and Prudence’.


Doyle family crest: a stag on top of a helmet over a shield depicting three stag heads

Pronunciation: Ó’Dubhghaill Oh duv-gall

Doyle is the twelfth most common surname in Ireland. It comes from the Irish Ó’Dubhghaill, and its exact meaning is unknown – some say it derives from Dubhgall, meaning ‘dark and tall’, while others say it is a portmanteau of Dubh (‘dark’) and Ghall (‘stranger’). The name possibly refers to 9th-century Viking or Danish settlers, who were darker than the native Celts. Nowadays, Doyles can be found in Leinster, and very rarely outside of this area.

The Doyle motto is ‘Fortitude Vincit, or ‘He Conquers by Fortitude’.

Possibly the most famous Doyle was Arthur Conan Doyle, author of the Sherlock Holmes stories.


McCarthy crest: an arm on top of a helmet over a white shield depicting a red stag

Pronunciation: Mac Cárthaigh Mak Car-tig

McCarthys are descended from Oilioll Olum, king of Munster. A powerful clan, the McCarthys had frequent skirmishes over territory. The name originates from the Irish Mac Cárthaigh (Cárthaigh meaning ‘loving’), which is thought to have been an ironic moniker used by their neighbours.

One branch of the clan lived and ruled from Blarney Castle. They also possessed the Blarney Stone, which supposedly gives those who kiss it the gift of gab.

Their motto is ‘Fortis Ferox et Celer’, meaning ‘Strong, Fierce and Fast’

McCarthys may have been ‘good at war’ in the past, but nowadays bearers of the name such as Cormac McCarthy, winner of a Pulitzer prize, also succeed in the arts.

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