Irish Last Names & Their Meanings (2023)

Irish Americans proudly display their heritage in their last names. The Kelly’s, the Murphy’s, the O’Connor’s and the Byrne’s – such names bring to mind the clans of old, the heady days of warring kerns and heroic galloglaighs. But where did these names come from? What is the story behind the Irish surnames that so many Americans carry to this day?

First Names First

Before understanding Irish last names, it is essential to remember that first names have meanings all their own. For example, look at the Irish surname O’Brian. The O has a meaning that we will cover below, but what about the Brian part? Such commonly used names should not be taken for granted, because they provide a key to our ancestors. Somewhere down the O’Brian genealogy line was the original Brian, himself. No O. Just Brian. The same goes for the original Donnell of the MacDonnells and the first Allen of the McAllens. The descendants of Brian (meaning “noble”), of Donnell (meaning “world-mighty”), and Allen (meaning “handsome”) remember that somewhere down the line their ancestor earned or was given that name.

The O’s, the Mac’s, the Mc’s and the Fitz

(Video) Frequency of Irish Surnames (1890s)

In the old country, in the days of yore, a person was not so much defined by who they were but by where they came from, who their father was, or their trade. The uppermost heights that a son could gain were the same as those of his father or grandfather.

The Mc in “McDonnell” and the Mac in “MacDonough” all mean “son of” in the native Gaelic, and all have survived and flourished as common prefixes to Irish surnames (though the original Mac is more common in Scotland). The feminine form, nic (meaning “daughter of”) is a rarity in modern Irish last names, which reflects the patriarchal society.

Son of…

Patrick, son of Brian, or Patrick mac Brian, was the given formula for how Irishmen would first describe themselves in the Middle Ages. In the meantime, Brian, the father of Patrick, would be known as Brian mac Connor, or the son of his own father, Connor. Mac – sometimes shortened to Mc – was said after the man’s given name and before the name of his father, denoting his male parentage. This method generally told enough of an Irishman’s story to identify him from others.

Unlike in modern times, where surnames are very much essential to our identity in day-to-day life, the early Irish rarely needed to use them. The fact was, in an isolated, tribal society (known as “tuaths”) where everyone came from the same place and very little family history was recordable, it just made more sense to say who your father was rather than give your ancestral line. Thus, Patrick, Brian, and Connor would all have different surnames (surnames meaning: sired by) as each of their fathers would probably have a different given name (though names such as “Patrick mac Patrick” did occur, i.e., junior).

(Video) What Irish Clan Do I Belong To?

Due to this generational change from one surname to another, it is difficult to trace Irish last names into the medieval period. However, like society itself, the tradition of Irish last names changed with the times. Feudalism, Catholicism, foreign invasions and intertribal wars brought pride in one’s lineage very much into vogue. Having an ancestor who was a landed lord, being the descendant of a saint, or someone in the line of ancient kings became incredibly important to the upper classes of medieval Irish society.

The First Irish Surname

The first Irishman with a recorded last name, TigherneachUa Cleirigh, was a lord who died in 916 C.E. in what is now modern-day Galway. The Ua denotes Tigherneach as being either the “son of,” “grandson of,” or “descendant of” Cleirigh (modern: Clery). The Ua would later become the O we are all familiar with in such names as O’Connell or O’Leary. This change to “grandson of” or “descendant of” is an important departure from simply saying “son of,” as it alters the narrative of a person’s name from “this is my dad” to “this is my family.” The most widely seen example of this comes from the name O’Brian, denoting a descendant of the legendary King Brian Boru… or giving a coincidental bit of luster to those with a different ancestor named Brian.

The Fitz

It would be the feudal lords and barons that first took on the mantle of Irish surnames to denote their familial lineage, and no one brought the hammer of feudalism quite like the Normans. In 1169 C.E. they invaded Ireland in a stunning sequel to their invasion of England in 1066, bringing with them their particular blend of oppression and progress. To say it was a rough go for anyone under the Norman boot is an understatement, but it is also how Irish surnames gained the prefix Fitz, as in Fitzpatrick. This Latinized form of “son of” is still a popular prefix found in Irish last names. Not only that, but the Normans – and, more so, their English successors – altered the “son of” formula that had heretofore been the most common source of surnames in Ireland.

(Video) Irish Family Names & Surnames, Spellings & Genealogy in 2 minutes

Irish Occupational Surnames

“Smith” is an incredibly common name in the English-speaking world. But who was this Smith? What did he or she do that was so magnificent to have so many modern ancestors still proudly bearing their namesake? Well, in a word: they smithed. They were blacksmiths, locksmiths, gunsmiths, goldsmiths, etc. In medieval England what a person did, or what their family business was, often determined their last name. This is why there are still so many Archers, Cooks, Coopers, Masons, Thatchers, Fishers, Butlers, and Wrights in England and, since the English occupation, in Ireland.

Such occupational surnames were fairly common in the early Irish lexicon, especially considering that specialized occupations were commonly passed down from parent to child. Irish surnames like O’Leary (from Ó Laoghaire, meaning calf-herder) or McLoughlin (from Mac Lochlainn, meaning Viking) tell the tale of sons who followed in the footsteps of their fathers. In fact, it wasn’t until the Normans and English established their feudal fiefdoms on the island and the markets and cities began to grow, that such names began to become invaluable. These last names immediately told a lord or merchant what you did and how you could help them. Think of them as business cards built into a name, an effective and subtle marketing tactic that a journeyman worker or skilled artisan would have been a fool to pass up.

Irish Toponymic Surnames

Trade brought toponymic last names to Ireland. Brian of Bray would become Brian Bray, while William from Wales became William Walsh. Barring a few examples, these names are not typical in Ireland, as strangers in a strange land – especially in less than tolerant times – are more inclined to assimilate rather than celebrate their differences. However, this is not the case with those who conquered…

(Video) (1) -- Location of Irish Family Names (Kevin Slean - Raheny - Dublin 5)

Anglicization: How Irish Last Names Changed

By the 1500s, traditional Irish Catholicism was put down in favor of English Protestantism and much of the native Irish population was resigned to second-class citizenship. This forced the Irish to Anglicize, to adapt and become more like their conquerors in order to survive these times. This is why so many Irish names have evolved beyond their Gaelic origins to fit more easily into the English language, some dropping the classic prefixes while others translated completely. Thus, Ó Ceallaigh became Kelly, Ó Murchadha became Murphy, while Mac Gabhann (the Irish occupational last name for a smith) became Smith.

The traditional Gaelic names changed under English rule. Anglicization became a way of survival for many Irish people during the last five centuries and resulted in the Irish surnames we all know today.

10 Common Irish Last Names & Their Meanings

Below are some of the most common Irish last names not discussed above. Our family history research is often guided by our surnames. Find your Irish last name in the list below or use our surname meaning search to find your name and learn more about your Irish heritage.

(Video) What Your Last Name Means

  • Byrne: meaning “raven,” the name is the seventh most popular in Ireland while the historic Byrne’s are notable for their resistance to foreign invaders.
  • Doyle: anglicized from Ó Dubhghaill, meaning “dark-haired foreigner,” Doyle was originally a term for the Danish Vikings who settled in Ireland in the early Middle Ages. The term was meant to differentiate them from the Norwegian Vikings, the Fionnghoill, or “fair-haired foreigners.”
  • Kelly: meaning “bright-haired” or “red-haired,” the last name Kelly is practically synonymous with Irishness, possibly due to the widely popular folk song “Kelly the Boy from Killane.”
  • Kennedy: the Irish surname made famous by J.F.K., Bobby, and their new American Camelot, Kennedy means “helmeted-head” in Gaelic. Despite its modern connotations of political royalty, the name is one of the most common in Ireland.
  • McCarthy: from Mac Carthaigh meaning “loving person,” the most widely known Carthaigh was a contemporary of the legendary king Brian Boru and one of his main rivals.
  • Murphy: the most common Irish surname deriving from the Gaelic MacMurchadh, meaning “sea-battler,” Murphy’s around the world owe their name to the notorious Irish sailors who raided the British coast before the Viking Age.
  • O’Connor: in Gaelic, Ó Conchobhair was a term that meant “patron of warriors.” The eponymous Conchobhair was the first king of Connaught, a county of Ireland that still bears his namesake.
  • O’Reilly: from the original Ó Raghallaigh meaning “extroverted one.” The historic O’Reilly’s are one of the most storied families in Ireland, even minting their own coins in the 15th century leading to the still-in-use Irish slang term “Reilly” to denote high value.
  • O’Sullivan: from the Gaelic Ó Súilleabháin, Sullivan has a variety of meanings, all to do with the eye. Some believe it means “dark-eyed,” while other theories suggest “one-eyed” or “hawkeyed.”
  • Ryan: combining the Gaelic words for little (an) and king (ri), Ryan simply means “little king.” Whether this was meant as a term of endearment or a good-natured insult is up for debate, though the name’s other translation, “illustrious,” would sway most to the former theory.

Who we are and where we came from can help us find out where we’re going. Newspapers hold the key to helping you uncover new details about your Irish ancestors’ lives, their trials and tribulations, and your family history. Search our collection of Irish newspapers published in the U.S. to trace your Irish ancestry.


What is a very Irish last name? ›

Common Irish Last Names
  • Murphy – ó Murchadha. ...
  • Kelly – ó Ceallaigh. ...
  • Byrne – ó Broin. ...
  • Ryan – ó Maoilriain. ...
  • O'Sullivan – ó Súilleabháin. ...
  • Doyle – ó Dubhghaill. ...
  • Walsh – Breathnach. ...
  • O'Connor – ó Conchobhair.
25 Apr 2022

What is the top 100 surnames in Ireland? ›

100 most Irish surnames revealed
RankNameIrish Equivalent
1Murphyó Murchadha
2Kellyó Ceallaigh
3O'Sullivanó Súilleabháin
96 more rows
2 Jan 2019

What is the oldest last name in Ireland? ›

The earliest known Irish surname is O'Clery (O Cleirigh); it's the earliest known because it was written that the lord of Aidhne, Tigherneach Ua Cleirigh, died in County Galway back in the year 916 A.D. In fact, that Irish name may actually be the earliest surname recorded in all of Europe.

What is the best Irish surname? ›

The Most Popular Irish Family Names
  • Murphy.
  • Byrne.
  • Kelly.
  • O'Brien.
  • Ryan.
  • O'Sullivan.
  • O'Connor.
  • Walsh.
17 Dec 2020

Can you be 100% Irish? ›

"'No one is 100 percent Irish,' he said," O'Brien added. Even in Ireland, people aren't 100 percent Irish, according to O'Brien's doctor. "You will find that the most Irish-looking people are like 86 percent, 94 percent Irish.

What is a rare Irish name? ›

Neala: Feminine form of the Irish Neal. Nola: Form of Fionnula, which means “white shoulder” Oona: Pretty name meaning “one” Riona: An Irish name that means “queenly” Saoirse: Pronounce this name SEER-sha.

What is the #1 last name? ›

The most common surname in the United States is Smith.

What is the most successful surname? ›

Most Common US Surnames By Rank
RankSurnameSurname Origin
2JohnsonEnglish, Scottish
3WilliamsEnglish, Welsh
4BrownEnglish, Scottish, Irish
96 more rows
19 Feb 2020

Is Irish DNA unique? ›

Irish People Have a Unique Mix of Ancestry

Invasions and cultural exchanges have led to a unique genetic blend in Ireland. If you're Irish , you could have any of these other groups in your DNA: Post-Ice Age Explorers.

Why the O is removed in Irish names? ›

5. In the 1600s, when English rule intensified, the prefixes O and Mac were widely dropped because it became extremely difficult to find work if you had an Irish sounding name. However, in the 1800s many families began reinstating the O and Mac prefixes.

Why is Irish last name with O? ›

Surnames and prefixes

A male's surname generally takes the form Ó/Ua (meaning "grandson/descendant of") or Mac ("son/descendant of") followed by the genitive case of a name, as in Ó Dónaill ("grandson/descendant of Dónall") or Mac Siúrtáin ("son/descendant of Jordan"). A son has the same surname as his father.

What are Irish gypsy last names? ›

Common Gypsy names

You may have Romani, Traveller or Gypsy ancestry if your family tree includes common Romani or Gypsy surnames such as Boss, Boswell, Buckland, Chilcott, Codona, Cooper, Doe, Lee, Gray (or Grey), Harrison, Hearn, Heron, Hodgkins, Holland, Lee, Lovell, Loveridge, Scamp, Smith, Wood and Young.

What language is llanfairpwllgwyngyllgogerychwyrndrobwllllantysiliogogogoch? ›

Llanfairpwllgwyngyllgogerychwyrndrobwllllantysiliogogogoch (llan-vire-pooll-gwin-gill-gore-ger-ih-queern-drorb-ooll-llandy-silio-gore-gore-goch), usually shortened to Llanfair-pwll or Llanfairpwllgwyngyll, is a Welsh word that translates roughly as "St Mary's Church in the Hollow of the White Hazel near a Rapid ...

Is llanfairpwllgwyngyllgogerychwyrndrobwllllantysiliogogogoch the longest word? ›

The long form of the name is the longest place name in the United Kingdom and one of the longest in the world at 58 characters (51 "letters" since "ch" and "ll" are digraphs, and are treated as single letters in the Welsh language).

What is the prettiest Irish name? ›

Irish Girls Names:
  1. Aoife (ee-fa) This name means beautiful, radiant or joyful, and likely derives from the Gaelic word 'aoibh' meaning 'beauty' or 'pleasure. ...
  2. Caoimhe (kwee-va or kee-va) ...
  3. Saoirse (ser-sha) ...
  4. Ciara (kee-ra) ...
  5. Niamh (neev or nee-iv) ...
  6. Roisin (ro-sheen) ...
  7. Cara. ...
  8. Clodagh (cloda)
12 Sept 2022

What surname means strong? ›

Fermi. The name Fermi has origins in Italian, and it means “strong.”

What are the 10 most common last names in Ireland? ›

The top 10 most popular Irish surnames and where they come from
  1. Murphy. The most common Irish surname, Murphy is believed to be derived from the old Irish surname Ó Murchadha meaning 'Son of the Sea Warrior'. ...
  2. Kelly. There are several theories on where Kelly came from. ...
  3. Byrne. ...
  4. Ryan. ...
  5. O'Brien. ...
  6. Walsh. ...
  7. O'Sullivan. ...
  8. O'Connor.
9 Mar 2016

What race is Irish? ›

The Irish are an ethnic group who come from or came from the island of Ireland. There are two countries on the island of Ireland: the Republic of Ireland and Northern Ireland. Historically, the Irish have been primarily a Celtic people.

What color is Irish skin? ›

The latest census figures from the Central Statistics Office (CSO) indicate that 93% of Ireland's population ('white-Irish' 82% and 'white-other' 9%) fall into the fair-complexion skin type 1 and 2 category.

Why do most Irish have red hair? ›

Irish people developed their red hair because of a lack of sunlight, according to new research from a leading DNA lab. Irelands DNA has revealed that one in 10 Irish people have red hair but it is thought that up to half the population could be carrying the redhead gene even though they are blonde or brunette.

What name means pure in Irish? ›

Caitlin. Caitlin is an Irish name for girls meaning “pure.” Traditionally, Caitlin, pronounced kath-LEEN, was anglicized as Cathleen or Kathleen.

What name means strong in Irish? ›

Brian. Brian is an Irish name meaning “noble” or “strong.”

What Irish name means freedom? ›

Saoirse. Saoirse (pronounced seer-sha) is a feminine name that rose to popularity during the 1920s. Given its meaning, freedom, it may well have been in response to Irish independence, which had dominated the previous decade and the early '20s.

What are the top 5 last names? ›

Most Common Last Names
26 more rows

What are the 20 most common last names? ›

100 Most Popular American Last Names
  • Smith.
  • Johnson.
  • Williams.
  • Jones.
  • Brown.
  • Davis.
  • Miller.
  • Wilson.

What is a royal last name? ›

For the most part, members of the Royal Family who are entitled to the style and dignity of HRH Prince or Princess do not need a surname, but if at any time any of them do need a surname (such as upon marriage), that surname is Mountbatten-Windsor.

Why is my surname so rare? ›

There are a number of reasons why you might have a rare surname. Names linked to niche professions that no longer exist, migration, colloquialisms and even entire families being wiped out during war could contribute to your family name being less common than others. Then again, it could simply be destiny.

What are the cutest last names? ›

40 of the cutest surnames that parents are using as forenames
  • Addison. Meaning: Addison is an English surname meaning 'son of Adam'.
  • Bardot. Meaning: Bardot is a French surname.
  • Bailey. Meaning: Bailey means 'steward or public official'.
  • Blaine. ...
  • Campbell. ...
  • Cassidy. ...
  • Cohen. ...
  • Ellison.

What last names no longer exist? ›

There is a list of names that are extinct. It includes Bread, Spinster, Chips, Rummage, Pussett, Temples, Wellbelove, Hatman and Bytheseashore. Know anyone with those names – hardly. Other names with just a few individuals include Fernsby, Rushlands, Berrycloth, Dankworth, Birdwhistle, Relish and Tumbler.

What last names mean loyal? ›

Amana. Amana is a popular female surname of Hebrew origin. It means trust, faithful, or loyal.

Who are the Irish genetically closest to? ›

Modern Irish are the population most genetically similar to the Bronze Age remains, followed by Scottish and Welsh, and share more DNA with the three Bronze Age men from Rathlin Island than with the earlier Ballynahatty Neolithic woman.

What is an Irish nose? ›

The characteristically “Irish” upward-pointed nose tip has long been praised, but that's not the only physical trait the Irish have going for them.

Do Irish people have O blood? ›

Blood group O Positive is the most common group in Ireland while AB negative is the least common.

Is there Z in Irish? ›

Letters and letter names

It does not contain ⟨j, k, q, v, w, x, y, z⟩, although they are used in scientific terminology and modern loanwords. ⟨zs⟩ (capitalized ⟨zS⟩) occurs in the West Muskerry dialect as the eclipsis of ⟨s⟩.

What does Fitz mean in Irish? ›

The prefix Fitz- is also found in Irish surnames. This term is Latin for “son of,” and was brought to Ireland by the Norman invaders in 1066. Examples of names using this patronymic prefix are Fitzpatrick, Fitzgerald, and Fitzsimmons.

What are Viking surnames in Ireland? ›

Other Norse names found occasionally in Ireland still include Cotter, Dowdall, Dromgoole, Gould, Harold, Howard, Loughlin, Sweetman and Trant.

Is White an Irish name? ›

White is a common surname across England, Scotland and Ireland, with examples dating back to the Saxon era. It's the seventeenth most popular name in England, and the twenty second most common in the United States. The surname White has a number of supposed origins.

Is McDonald Irish or Scottish? ›

MacDonald, Macdonald, and McDonald are surnames of both Irish and Scottish Origin. In the Scottish Gaelic and Irish languages they are patronymic, referring to an ancestor with given name Donald.

How do I find my Irish clan? ›

The National Archives of Ireland's genealogy portal is one of the key websites for tracing Irish ancestry. It offers free access to the surviving census fragments from 1901/1911, as well as substitute sources. You can search raw census data, then view PDF copies of the original documents.

Is King an Irish name? ›

King Family History

Meaning 'ruler', variants of the name King include Conroy, O'Conry and O'Mulconry. This name is of Celtic origin and is found throughout England, Ireland, Scotland and Wales. It is found in many mediaeval manuscripts in these countries.

Are Gypsies Irish? ›

There are around 300,000 Gypsy Roma and Irish Travellers in the UK – Roma Gypsies are originally from northern India, whereas Travellers are of Irish origin – and both groups are nomadic.

What is a black Irish Gypsy? ›

Mixed Gypsy/Romani or the Irish Travelers

Myths point out that they were exiled from India into Europe after an Afghani King invaded northern India in the 15th Century. It is sometimes believed that these Gypsies intermarried with the white Irish and produced the BlackIrish People.

What is the oldest last name? ›

Until the Shang Dynasty (1600-1046 BC), people seemed to use matrilineal surnames, but afterward, they had switched to using patrilineal ones. The oldest surname known to have been recorded anywhere in Europe, though, was in County Galway, Ireland, in the year 916. It was the name “O Cleirigh” (O'Clery).

What is the #1 last name in the world? ›

Yet there's no doubt about which surname is the most popular in the world: Wang. More than 106 million people have the surname Wang, a Mandarin term for prince or king. It's not too surprising that the top surname is Chinese, as China has the world's largest population.

What is the oldest bloodline? ›

The longest family tree in the world is that of the Chinese philosopher and educator Confucius (551–479 BC), who is descended from King Tang (1675–1646 BC). The tree spans more than 80 generations from him and includes more than 2 million members.

Do the Irish have Viking blood? ›

New research shows that the Irish definitely have their fair share of Viking heritage–in fact, the Irish are more genetically diverse than most people may assume. The Irish have Viking and Norman ancestry in similar proportions to the English.

Are Irish and Vikings the same? ›

English Vikings show sharp ancestral differences with their Irish counterparts, with much stronger Danish influences. Many Vikings had brown hair, not blonde, including the famous Eyrephort warrior from Co. Galway. Viking identity in Britain and Ireland was not limited to those of Scandinavian ancestry.

Is there Viking DNA in Ireland? ›

“In general, Irish Viking genomes harbour high levels of Norwegian-like ancestry. This is a real contrast to what we see in England during the same period, where there is stronger Danish influence.” The study also revealed that Viking identities were taken up by local people in Britain and Ireland.

What DNA do Irish Travellers have? ›

Irish Travellers are of Irish ancestral origin and have no particular genetic ties to European Roma groups, a DNA study has found. The research offers the first estimates of when the community split from the settled Irish population, giving a rare glimpse into their history and heritage.


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