Popular Irish Surnames and Last Name Meanings

The Origins of Irish Surnames

Irish surnames are among the oldest hereditary family names in the world, with origins dating back to the 10th century. Unlike in many other cultures, surnames in Ireland were not initially used to identify occupations or locations but were deeply connected to lineage, clans, and ancestry.

The use of prefixes like "O'" and "Mac" is a defining feature. "O'" comes from "Ó," meaning "descendant of," while "Mac" means "son of." For example, "O’Connor" translates to "descendant of Conchobhar," and "MacCarthy" means "son of Carthach."

Gaelic, the traditional language of Ireland, plays a central role. Names were phonetic and descriptive, often referencing the first patriarch in a family line or a distinguishing personal trait. Over time, names were anglicized through colonization and immigration, making the original Gaelic versions rare but still traceable.

Unique and Unusual Irish Last Names

While names like Murphy and Kelly are well-known, Ireland is also home to hundreds of lesser-known surnames with rich stories.

• Ó Ciardha (Carey): Derived from "ciar" meaning dark or black, it originally signified someone with dark features.

• Mac Gafraidh (McCaffrey): A Northern Irish name from the Fermanagh area, meaning "son of Gafraidh," a personal name of Norse origin.

• Ó hAodha (Hayes): Translating to "descendant of Aodh," the name Aodh was the Gaelic god of fire.

• Ó Scealláin (Scallan): Originates from Wexford and Waterford, meaning "descendant of Sceallán," possibly derived from "sceall," meaning shell or peel.

These rare surnames carry the identity of forgotten clans and offer deep insight into Ireland's complex regional and tribal past.

Popular Irish Surnames and Meanings

Many Irish surnames are recognized globally due to the Irish diaspora. Below are some of the most popular:

• Murphy (Ó Murchadha): Ireland’s most common surname. It means "descendant of Murchadh," a name meaning sea warrior.

• Kelly (Ó Ceallaigh): Comes from "Ceallach," meaning strife or war. One of the most widespread Irish surnames.

• Sullivan (Ó Súilleabháin): Means "descendant of Súilleabhán," which roughly translates to "dark-eyed."

• Walsh: Originally meaning "foreigner" or "Welshman," it denotes those who came to Ireland from Britain.

• Ryan (Ó Riain): Derived from "Rian," possibly meaning "little king."

• Byrne (Ó Broin): Means "descendant of Bran," which translates to raven, a powerful Celtic symbol.

These surnames are not just identifiers—they are windows into Ireland’s mythological, linguistic, and tribal history.

Traditional and Old Irish Surnames

Ancient Irish surnames often trace back to High Kings, warriors, and poets. These traditional names are steeped in legend:

• O’Neill (Ó Néill): Derived from Niall of the Nine Hostages, a legendary king who kidnapped St. Patrick.

• MacMahon (Mac Mathghamhna): Means "son of the bear," indicating strength and power.

• O’Brien (Ó Briain): Comes from Brian Boru, the High King who defeated the Vikings at Clontarf.

• MacMurrough (Mac Murchadha): Once rulers of Leinster, this name means "son of Murchadh."

• Ó Donnchadha (O'Donoghue): Meaning "descendant of Donnchadh," or brown warrior.

These surnames are often found carved into ancient headstones, referenced in Irish legends, and still worn with pride today.

Famous Irish American Last Names

With over 33 million Americans claiming Irish ancestry, it’s no surprise that many bear proudly Irish surnames:

• Kennedy: From "Ó Cinnéide," meaning helmeted head. This political dynasty has become synonymous with American and Irish heritage.

• Reagan: Derived from "Ó Ríagáin," meaning little king. Known for U.S. President Ronald Reagan.

• Fitzgerald: From Norman-Irish roots, "son of Gerald," with links to both royalty and rebellion.

• McCarthy: From Mac Carthaigh, an old noble Munster family.

• Quinn: From "Ó Cuinn," meaning wisdom or chief. Widespread across the U.S. and Ireland alike.

These names highlight the strong cultural bridge between Ireland and the Irish diaspora, particularly in North America.

Connect with Your Heritage: Dive into the Intriguing World of Irish Surnames!

Uncovering your surname can be the first step in discovering your Irish identity. From regional maps and heraldry to DNA kits and family crests, today’s tools make it easier than ever to connect with your Gaelic roots.

At The Irish Jewelry Company, we celebrate this heritage through our stunning collection of personalized Irish jewelry. From Claddagh rings engraved with your family name to family crest pendants, your ancestry can be cherished and passed down through generations.

Explore the ancient history of your surname and wear it with pride. Your last name is more than a label—it’s your legacy.

Gaelic or Irish surnames are “patronymics,” which means they indicate patrilineal descent, such as “son of “. Frequentl,y the Irish and Scottish used Gaelic prefixes with Irish surname meanings. Prefixes such as Mac or Mc, which is the Gaelic word for “son”. So, for the son, Mac was attached to the father’s name or trade. Likewise, O is a word all by itself in Gaelic, for “grandson” when used before a grandfather’s name or trade. As Gaelic names became Anglicized, the English surname sometimes lost its prefixes:

List of Popular Irish Surnames and Irish Surname Meaning

Over one hundred Irish surnames or last names, together with their respective meanings, pronunciations, and additional information, may be found in the following last name guide.

Brennan

This Irish surname was prevalent, settling in Fermanagh, Galway, Kerry, Kilkenny, and Westmeath. The Brennan surname in Ireland is now mostly found in County Sligo and the province of Leinster.

Irish spelling: Ó Braonáin/Ó Branáin
Meaning: Ó Braonáin means of the droplet, while Ó Branáin means of the raven.

Brown or Browne

Common in both England and Ireland, the Irish Brown families are mostly found in the province of Connacht (specifically Galway and Mayo), as well as Kerry.

Meaning: It denotes the brown complexion of the skin or brown hair color.

Boyle

The O'Boyles were chieftains in Donegal, ruling west Ulster with the O'Donnells and the O'Doughertys. Boyle descendants can also be found in Kildare and Offaly.

Irish spelling: Ó Baoill
Meaning: Vain pledge.

Burke

The Norman last name Burke originated from the borough of Caen in Normandy (de burg means “of the borough”). The Burkes have been in Ireland since the 12th century, settling mainly in the province of Connacht.

Meaning: refers to a ‘fortress’ or ‘castle.’

Byrne / Burns

The O Byrne (Ó Broin) family originally came from Kildare, until the Anglo-Normans arrived, and they were driven south to the Wicklow mountains. The Byrne surname is still quite common in Wicklow, as well as Dublin and Louth.

Irish spelling: O’Byrne’ or ‘Ó Broin

Meaning: descendant of Bran’ where Bran refers to a ‘raven

Callaghan

The Callaghans were a powerful family in the province of Munster. Individuals with the Irish surname Callaghan (also spelled Callahan) are most numerous in Clare and Cork.

Irish spelling: Ó Ceallacháin
Meaning: the Eoghanacht, descent from Ceallachan

Campbell

Campbell families are very prevalent in Donegal (most are descended from Scottish mercenary soldiers), as well as in Cavan. Campbell is a descriptive surname meaning “crooked mouth.”

Irish spelling: Mac Cailein
Meaning: Scottish Gaelic words referring to crooked mouth or wry-mouthed

Carroll

The Carroll surname (and variants such as O’Carroll) can be found throughout Ireland, including Armagh, Down, Fermanagh, Kerry, Kilkenny, Leitrim, Louth, Monaghan, and Offaly. There is also a MacCarroll family (anglicized to MacCarvill) from the province of Ulster.

Irish spelling:  Ó Cearbhaill

Meaning: hacking with a weapon

Clark(e)

One of the oldest surnames in Ireland, the O Clery surname (anglicized to Clarke) is most prevalent in Cavan.

Irish spelling: Ó Cleireigh(Clery)

Meaning: ‘clergy’ or ‘priest

Collins

The common Irish surname Collins originated in Limerick, though after the Norman invasion, they fled to Cork. There are also Collin families from the province of Ulster, most of whom were probably English.

Irish spelling: Ó Coileáin
Meaning: Descendent of the young warrior/hound.

Connell / O’Connell

Three distinct O Connell clans, located in the provinces of Connacht, Ulster, and Munster, are the originators of many of the Connell families in Clare, Galway, Kerry.

Irish spelling:  Ó Conaill

Connolly

Originally an Irish clan from Galway, the Connolly family settled in Cork, Meath, and Monaghan.

Irish spelling: Ó Coingheallaigh

Meaning: nickname for ‘someone as valiant as a wolf’ and later evolved as a last name in Ireland.

Connor

In Irish Ó Conchobhair or Ó Conchúir, the Connor last name means “hero or champion.” The O Connor family was one of three royal Irish families; they are from Clare, Derry, Galway, Kerry, Offaly, Roscommon, Sligo, and the province of Ulster.

Irish spelling: Conchobhair

Meaning: Old Irish and means a ‘wolf’ or a hound dog.

Daly

The Irish Ó Dálaigh comes from dáil, meaning a place of assembly. Individuals with the Daly surname hail primarily from Clare, Cork, Galway, and Westmeath.

Irish spelling: Ó Dálaigh
Meaning: Of the assembly.

Doherty / Daugherty

The name in Irish (Ó Dochartaigh) means obstructive or hurtful. In the 4th century, the Dohertys settled around the Inishowen peninsula in Donegal, where they’ve primarily stayed. The Doherty surname is the most common in Derry. Also spelled Dougherty and Daugherty.

Irish spelling: Ó Dochartaigh

Meaning: meaning the ‘descendant of Dochartach.’ ‘Dochartach’ means ‘obstructive’ or ‘dangerous.’

Doyle

The Doyle last name comes from dubh ghall, the “dark foreigner,” and is thought to be Norse in origin. In the province of Ulster, they were known as Mac Dubghaill (MacDowell and MacDuggall). The greatest concentration of Doyles is in Leinster, Roscommon, Wexford, and Wicklow.

Irish spelling: Ó Dubhghaile
Meaning: Descendent of Dubhghal, meaning black valor.

Duffy

Ó Dubhthaigh, anglicized to Duffy, comes from an Irish name meaning black or swarthy. Their original homeland was Monaghan, where their surname is still the most common. They are also from Donegal and Roscommon.

Irish spelling: Ó Dufaigh/Ó Dubhthaigh
Meaning: Black.

Dunne/ Dunn

From the Irish for brown (donn), the original Irish name Ó Duinn has by now lost the O prefix. In the province of Ulster, the final e is omitted. Dunne is the most common surname in Laois, where the family originated. Also occasionally spelled Donne.

Irish spelling: Ó Doinn or Duinn

Meaning: Old English word for ‘dark’ or from ‘donn’ the Gaelic word for ‘brown.’

Farrell

The O Farrell chieftains were lords of Annaly near Longford and Westmeath. Farrell is a surname generally meaning “valiant warrior.”

Irish spelling: Ó Ferghail
Meaning: Man, of valor.

Fitzgerald

A Norman family who came to Ireland in 1170, the Fitzgeralds (spelled Mac Gearailt in parts of Ireland) claimed vast holdings in Cork, Kerry, Kildare, and Limerick. The surname Fitzgerald translates directly as “son of Gerald.”

Meaning: the name ‘Gerald’ refers to ‘rule of the spear.’

Flynn

The Irish surname Ó Floinn is prevalent in the province of Ulster. However, the “F” is no longer pronounced, and the name is now Loinn or Lynn. The Flynn surname can also be found in Clare, Cork, Kerry, and Roscommon. It is a patronymic Irish surname meaning ‘son of Gerald.

Irish spelling: Ó Floinn

Meaning: name ‘Flann’ refers to ‘reddish’ or ‘scarlet’ in Gaelic.

Gallagher

The Gallagher clan has been in County Donegal since the 4th century, and Gallagher is the most common surname in this area. Descendent of Gallchobhar, an Irish king. Gallagher is the anglicized form of ‘Ó Gallchobhair’, meaning a ‘descendant of Gallchobhar.’

Irish spelling: Ó Gallchobhair
Meaning: two Irish word,s ‘gall’ meaning ‘stranger’ and ‘cabhair’ meaning ‘help.’

Healy

The Healy surname is mostly found in Cork and Sligo.

Irish spelling: Ó hÉalaighthe

Meaning: referring to a ‘descendant of the claimant.’

Hughes

The Hughes surname, both Welsh and Irish in origin, is most numerous in three provinces Connacht, Leinster, and Ulster.

Irish spelling: Ó hAodha

Meaning: name ‘Aodh’ is derived from ‘Aed,’ an Old Irish word for ‘fire.’

Kelly

Kelly families of Irish origin come primarily from Derry, Galway, Kildare, Leitrim, Leix, Meath, Offaly, Roscommon, and Wicklow.

Irish spelling: Ó Ceallaigh
Meaning: ‘Ceallach’ refers to ‘bright-headed.’

Kennedy

The Kennedy surname, both Irish and Scottish in origin, hails from Clare, Kilkenny, Tipperary, and Wexford.

Irish spelling: Ó Cinnéide
Meaning: anglicized form of ‘Ó Cinnéidigh’ which means ‘descendant of Cennetig.’ ‘Cennetig’ is an Old Irish word referring to an ‘armored head’ or ‘misshapen head.’

Lynch

The Lynch families (Ó Loingsigh in Irish) were originally settled in Clare, Donegal, Limerick, Sligo, and Westmeath, where the Lynch surname is most common.

Irish spelling: Ó Loinsigh
Meaning: Descendant of Loingseach, a seaman. occupational surname referring to a ‘mariner.’

MacCarthy/ McCarthy

The MacCarthy surname originated primarily from Cork, Kerry, and Tipperary. Also spelled McCarthy.

Irish spelling: Mac Carthaigh
Meaning: Son of Cárthach, King of Munster (Ireland’s southern province).

Maguire

The Maguire surname is the most common in Fermanagh. Also spelled McGuire. Maguire is an Irish clan surname from the Gaelic Mac Uidhir, meaning “son of Odhar” or “son of the pale-colored one.”

Irish spelling: Mag Uidhir

Meaning: MacCarthy refers to a ‘son of Carthach’ and Carthach means ‘loving.’

Mahony

Munster was the territory of the Mahoney clan, with Mahonys (or Mahoneys) being most numerous in Cork. Brodceann O’Mahony was the eldest of the four sons of Mathghamain, known as “The Four Descendants”. The O’Mahonys were Cenél nÁeda princes of the ancient Eóganacht Raithlind.

Irish spelling: Ó Mathghamhna (modern spelling O’Mathúna)

Meaning: ‘bear’.

Martin

The Martin surname, common in both England and Ireland, can be found primarily in Galway, Tyrone, and Westmeath.

Irish spelling: Mac Giolla Mhartain

Meaning:

Moore

The ancient Irish Moores settled in Kildare, while most Moores are from Antrim and Dublin.

 Irish spelling: Ó Mordha, Muir, Moir
Meaning: Moir/Ó Mordha could mean greatness or grandiose, while Muir means sea.

Murphy

The most common of all Irish names, the Murphy surname, can be found in all four provinces. Murphys are primarily from Antrim, Armagh, Carlow, Cork, Kerry, Roscommon, Sligo, Tyrone, and Wexford, however.

Irish spelling: Ó Murchadha
Meaning: Descendant of Murchadh, a sea warrior.

Murray

The Murray surname is especially prolific in Donegal.

Irish spelling: Ó Muireadhaigh
Meaning: Descendant of Muireadhaigh, a seaman. Muireadhach is a variant of ‘Muiredach’ referring to ‘lord’ in Irish.

Nolan

Nolan families have always been very numerous in Carlow, and can also be found in Fermanagh, Longford, Mayo, and Roscommon. It is an anglicized version of ‘Ó Nuallain’ referring to ‘descendant of Nuallan.

Irish spelling: Ó Nuallain

Meaning: Nuallan means ‘noble’ or ‘famous.’

O’Brien

One of Ireland’s leading aristocratic families, the O Briens are is primarily from Clare, Limerick, Tipperary, and Waterford. It originates from ‘Ó Briain,’ which means ‘descendant of Brian.

Irish spelling: Ó Briain
Meaning: Descendant of Brian Boru, the High King of Ireland. Brian means ‘high’ or ‘noble.’

O’Donnell

The O Donnell clans originally settled in Clare and Galway, but today they are most numerous in County Donegal. Sometimes modified to O’Donnelly. It is the anglicized variant of ‘Ó Domhnaill’ which means ‘descendant of Domhnall.’

Irish spelling: Ó Domhnaill

Meaning: Domhnall is the Gaelic version of the phrase ‘ruler of the world.’

O’Neill

One of three royal Irish families, the O'Neills are from Antrim, Armagh, Carlow, Clare, Cork, Down, Tipperary, Tyrone, and Waterford. This surname refers to ‘descendant of Neil.’

Irish spelling: Ó Néill
Meaning: Descendant of Niall Noigiallach, an Irish king. Neil comes from ‘Niall,’ a Gaelic word with several meanings, namely ‘cloud,’ ‘champion,’ or ‘passionate.’

Quinn

From Ceann, the Irish word for head, the name Ó Cuinn means intelligent. In general, Catholics spell the name with two ns, while Protestants spell it with one. The Quinns are primarily from Antrim, Clare, Longford, and Tyrone, where their surname is the most common. It is an anglicized version of ‘Ó Cuinn’ that means ‘descendant of Conn.’

Irish spelling: Ó Cuinn

Meaning: Conn refers to a ‘chief’ in Gaelic.

(O) Reilly

Descendants of the O Conor kings of Connacht, the Reillys are primarily from Cavan, Cork, Longford, and Meath.

Irish spelling: Ó Raghallaigh

Meaning:

Ryan

The Ó Riain and Ryan families of Ireland are primarily from Carlow and Tipperary, where Ryan is the most common surname. They can also be found in Limerick. This Irish surname is an anglicized version of ‘Ó Riain’, meaning ‘descendant of Rian.’

Irish spelling: Ó Riain
Meaning: Descendant of Riain, a king. Rian refers to ‘little king.’

Shea/ O’Shea

Originally, the Shea family was from Kerry, though they later branched out to Tipperary during the 12th century and Kilkenny by the 15th century. Sometimes modified to Shay.

Irish spelling: Ó Séaghdha
Meaning: Descendent of the majestic.

Smith

The Smiths, both English and Irish, are primarily from Antrim, Cavan, Donegal, Leitrim, and Sligo. Smith is the most common surname in Antrim.

Smith/McGowan
Irish spelling: Mac Gabhann
Meaning: Son of the blacksmith.

(O) Sullivan

Originally settled in County Tipperary, the Sullivan family spread into Kerry and Cork, where they are now most numerous, and their surname is the most common. It is an anglicized form of ‘Ó Súileabháin,’ meaning ‘descendant of Suileabhan.’

Irish spelling: Ó Suileabháin

Meaning: name ‘Suileabhan’ refers to the phrase ‘little dark eye.’

Sweeney

Sweeney families are found primarily in Cork, Donegal, and Kerry.

Irish spelling: Mac Suibhne
Meaning: Son of Suibhne, a Scottish lord whose grandson arrived to Ireland and brought the name with him.

Thompson

This English name is the second most common non-Irish name found in Ireland, especially in Ulster. The Thomson surname, without the “p,” is Scottish. Thomson is most common in Down.

Irish spelling: Mac Tomáis

Meaning:   son of Thom

Walsh

The name came into use to describe the Welsh people who came to Ireland during the Anglo-Norman invasions. Walsh families were very numerous throughout all four provinces of Ireland. Walsh is the most common surname in Mayo.

Irish spelling: Breathnach
Meaning: Welshman.

White

White families can be found in Ireland throughout Down, Limerick, Sligo, and Wexford. It is a descriptive name given to a person who was fair-haired or had a pale complexion, from the Middle English “whit,” meaning “white.” Fionn mac Cumhail was a legendary Irish hero who became all-wise by eating an enchanted salmon. He fought against the giant Fomors with his son Oisín and grandson Oscar.

Irish spelling:  Fionn (older Irish finn)

Meaning: a person who was fair-haired or had a pale complexion, meaning “fair” or “white“.

Connect with Your Heritage: Dive into the Intriguing World of Irish Surnames!

Uncovering your surname can be the first step in discovering your Irish identity. From regional maps and heraldry to DNA kits and family crests, today’s tools make it easier than ever to connect with your Gaelic roots.

At The Irish Jewelry Company, we celebrate this heritage through our stunning collection of personalized Irish jewelry. From Claddagh rings engraved with your family name to family crest pendants, your ancestry can be cherished and passed down through generations.

Explore the ancient history of your surname and wear it with pride. Your last name is more than a label—it’s your legacy.

Frequently Asked Questions About Irish Last Names

What is the most common Irish surname?

The most common surname in Ireland is Murphy. With roots in the Gaelic "Ó Murchadha," it means "descendant of sea warrior."

Why do so many Irish surnames start with "O'?"

"O'" means "descendant of" and was used to identify family lineage. It reflects the Gaelic clan system, where identity came from ancestry.

How do Irish surnames differ from Scottish ones?

While both cultures use prefixes like "Mac," Irish surnames often use "O'" and are tied more closely to Gaelic tribes. Scottish surnames often denote locations or occupations and reflect both Gaelic and Norse influences.

What are some old Irish last names?

Some of the oldest include O'Brien, O'Neill, MacMurrough, O'Donoghue, and MacCarthy. These names go back over 1,000 years and are found in ancient texts and gravestones.

Where is the origin of Irish names?

Irish surnames originated in Gaelic Ireland around the 10th century. Many derive from mythical figures, ancient chieftains, and regional tribes.

Connect Us

Ready to connect with your heritage? Contact us at The Irish Jewelry Company to learn more about Irish name jewelry and heritage gifts.

About the Author

Jennifer Derrig, founder and designer at The Irish Jewelry Company, is an expert in Irish culture and symbolism. With a passion for genealogy and Celtic heritage, her work brings ancient stories to life through design.

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