Discover 120 Irish Family Names and Their Meanings — A Journey Through Ireland’s Heritage and Clans
by Teresa Finn on Nov 13, 2025
Table of Content
Origins and Structure of Irish Surnames
Irish surnames are among the oldest hereditary names in Europe. Most follow Gaelic naming traditions, with prefixes such as O’ (meaning “descendant of”) and Mac/Mc (meaning “son of”). During British rule, many names were anglicized, which is why you’ll find both Gaelic and English spellings today. Some surnames even reflect Norse and Norman influence, especially along the coasts.
From the Irish clan system and ancient septs to modern counties, each surname tells a story of lineage, place, and personality. Now, let’s dive into the most common Irish last names and their meanings that have defined Ireland for centuries.
The Story Behind Irish Family Names and What They Mean
Patronymic Names
Every Irish name has a heartbeat. Passed down through clans, told in songs, whispered in stories — these Irish family names hold the pride of generations. Some recall ancient kings and warriors, others humble poets or farmers, yet each carries the same unshakable love for Ireland’s heritage and history.
O’Brien (Ó Briain) — Grandson/descendant of Brian; linked to Brian Boru, iconic High King of Ireland
O’Connor / Connor (Ó Conchobhair) — Descendant of Conchobhar
O’Kelly (Ó Ceallaigh) — Anglicized form of Ó Ceallaigh
O’Leary — Descendant of Laoghaire
O’More — Scottish and Gaelic origins; also Moore, Muir, Mure
O’Murphy (Ó Murchadha) — Anglicized Ó Murchadha
O’Neill (Ó Néill) — Descendant of Niall
O’Driscoll (Ó hEidirsceoil) — “Bearer of news”
O’Carroll (Ó Cearbhaill) — Meaning “disputed” in the historical gloss
O’Houlihan (Ó hUallacháin) — “Proud”
O’Keefe — “Descendant of Caoimh” (gentle or noble)
O’Sullivan (Ó Súilleabháin) — “Dark-eyed” or “hawk-eyed” (consolidated with the base “Sullivan”)
O’Donnell — From the powerful O’Donnell kindred of Clare and Galway
Fitzgerald — “Son of Gerald,” a classic Norman-Irish Fitz name
Fitzpatrick — “Devotee of St Patrick,” from Mac Giolla Phádraig
McCarthy (Mac Cárthaigh) — “Son of Cárthach,” kingship in Desmond lines
McMahon (Mac Mathghamhna) — “Son of the bear”
McManus (Mac Mághnais) — “Son of Magnus”
McGovern (Mág Samhradháin) — “Son of Samhradhán”
McKeogh (Mac Eochaidh) — “Son of Eochaidh”
McGee / Magee (Mac/Mag Aodha) — “Son of Aodh”
MacDermott — “Son of Diarmaid,” linked with Connacht chieftains
Maguire (Mac Uidhir) — “Son of Odhar” or “dark one”
Tip: If you’re mapping heritage clothing or Irish plaids by family name, patronymic lines often correlate with regional tartan preferences. If no clan tartan exists, the Irish National Tartan is a respectful, inclusive option.
Descriptive or Character-Based Names
These traditional Irish surnames read like little poems. They can reference color, character, courage, or even a youthful spirit. If you like etymology, this is where the meaning of Irish family names really shines.
Campbell — “Crooked mouth” or “wry mouth” (Scottish in origin but deeply woven into Irish life)
Casey — “Vigilant” in Old Irish usage
Collins — From a Gaelic root meaning “whelp” or “young dog” and later “darling”
Duffy — “Dark” or “swarthy”
Farrell — “Valiant warrior” or “man of valor”
Flynn — “Scarlet” or “red,” associated with red hair
Hogan — From a Gaelic root meaning “young” or “youthful warrior”
Kennedy (Ó Cinnéide) — “Armored head” or “misshapen head,” famous worldwide
Quinn — “Chief,” from Ó Coinn / Mac Cuinn lines
Regan — From Riagán, “impulsive”
Brady (Ó Brádaigh) — “Broad” or “spirited”
Flanagan (Ó Flannagáin) — “Red” or “ruddy”
Flannery (Ó Flannghaile) — “Red valor”
Molloy (Ó Maolmhuaidh) — “Proud chieftain”
Tracy (Ó Treasaigh) — “Fighter”
Heany (Ó hEignigh) — “Horseman”
Dempsey (Ó Díomasaigh) — “Proud”
Keane (Ó Catháin) — Interpreted as “courageous warrior”
Foley — “Plunderer”
Higgins (Ó hUiginn) — Glossed as “sea rover” in many summaries
Smith (Mac Gabhann) — Gaelic occupational root “smith”.
Regional Irish Surnames and Clan Origins
Surnames often concentrate around certain counties or provinces—a gift for anyone doing Irish genealogy. Think of these as breadcrumbs that lead to specific septs and landscapes. This is where Irish surnames by region come to life.
Boyle (Ó Baoighill) — Common in Kildare and Offaly; O’Boyles were Donegal chieftains
Byrne (Ó Broin) — Dense in Wicklow, Dublin, Louth; connected to “raven”
Clarke — One of Ireland’s oldest surnames; most prevalent in Cavan
Deasun — Signifies people from South Munster
Dunne (Ó Duinn / Ó Doinn) — Most common in Laois
Martin — Found in Tyrone, Galway, and Westmeath
Ryan (Ó Riain / Ó Maoilriain) — Most common in Tipperary and Carlow; “little king”
Shea (Ó Sé) — From Kerry; “esteemed” or “majestic”
Bell — A Borders-origin clan name that appears in Irish records
Brennan (Ó Branáin/Ó Braonáin) — A widely occurring clan surname across Ireland
Connell / Connelly — Originating in Connacht, Ulster, and Munster; later strong in Galway, Cork, Meath, Monaghan
Gallagher (Ó Gallchobhair) — Ancient Donegal lineage
Hayes (Ó hAodha) — “Fire,” originating in Cork
Murray (Ó Muireadhaigh) — Ties between Ireland and Scotland
Boylan (Ó Baoighealláin) — “Descendant of Baoigheallán”
Boland (Ó Beólláin) — “Descendant of Beóllán”
Ward (Mac an Bhaird) — “Son of the bard”
Gaffney (Ó Gamhna) — “Calf”
Geoghegan (Mag Eochagáin) — “Horse”
Scully (Ó Scolaidhe) — “Descendant of Scolaidhe”
Madden (Madadhan) — “Little dog”
Mulligan (Ó Maolagáin) — “Grandson of the bald man”
Gorman (Mac Gormáin) — “Dark blue” or “noble”
Keenan (Ó Cianáin) — “Descendant of the faithful one”
Colgan (Ó Colgáin) — “Sword”
Cosgrave (Ó Coscraigh) — “Son of Coscrach”
Egan (Mac Aodhagáin) — “Little bright-eyed one”
Phelan / Whelan (Ó Faoláin) — “Wolf”
Nolan (Ó Nualláin) — “Famous” or “noble”
Kearney (Ó Catharnaigh) — Often glossed as “victorious”
Coughlan (Mac/Ó Cochláin) — “Son of the one with the cloak”
Ahearn — Established Irish surname with Gaelic derivation
Buckley — Recognized Irish surname with Gaelic origin in Munster
Callaghan — Gaelic-rooted surname in Irish records
Carkel — One of the oldest; strongest in Cavan
As you trace locations, remember that names migrated. A Ryan in Limerick today might descend from a Tipp line, while a Walsh in Wexford could trace to Norman-Welsh arrivals. That movement is part of the beauty of Irish heritage and culture.
Irish Surnames with Norse/Norman Threads
The island’s coasts and castles remember Vikings and Normans. You’ll spot the imprint in both name structure (hello again, Fitz) and in meanings like “foreigner” or “Welshman”. This isn’t a betrayal of Gaelic identity—it’s a history lesson written in the language of family.
Doyle (Ó Dubhghaill) — “Descendant of the dark foreigner,” typically pointing to Norse
Walsh (Breathnach) — “Welshman/foreigner,” a Norman-era marker
Barry — Entwined with Norman families in Munster
Donovan — “Descendant of the dark brown-haired chieftain”. Interactions with Norman power spheres in Munster history
Fitzpatrick — Norman structure blended with Gaelic devotion
Unique and Traditional Irish Surnames
Some names feel like heirlooms—ancient, evocative, and sometimes rare in modern phone books. If you’re curating a heritage wall or choosing Irish plaids by family name for a family reunion, these can be striking centerpieces.
Fagan — “Descendant of Faodhagán,” fiery or ardent
Sweeney (Mac Suibhne) — “Pleasant”
Tierney (Ó Tiarnaigh / MacTighearnian) — “Master”
O’Cleary (Ó Cléirigh) — “Clerk” or “cleric”
McCloskey (Mac bhLoscaidh) — “Son of Bloscadh”
Cahill — “Strong in battle”
Canavan (Ó Ceanndubháin) — “Descendant of the dark-haired one”
Dwyer — “Dark colored”
Cullen (Ó Cuileáin) — “Young hound” or “handsome one”
Finnegan (Ó Fionnagáin) — “Son of the fair-haired”
Donohoe (Ó Donnchadha) — “Brown-haired” or “battle”
Donnelly (Ó Donnghaile) — “Brown valor”
Connolly (Ó Conghalaigh) — “Fierce as a hound”
Brogan — A recognized Irish surname with early Gaelic roots, often linked with early Christian and monastic Ireland.
Balfe — A recognized Irish surname with a Gaelic origin
Famous Irish-American Last Names
Irish names didn’t stop at the Atlantic. They sailed, settled, worked, and wove into American life—from tenement stoops to presidential podiums. These surnames echo in ballads, box scores, and ballots.
Moloney — “Descendant of the servant of the church”
Maher (Ó Meachair) — “Descendant of a kind chief”
Moran (Ó Móráin) — “Big chieftain”
Mullen (Ó Maoláin) — “Descendant of Maolán”
Healy (Ó hEalaighthe) — “Ingenious”
Hughes (Ó hAodha) — “Descendant of Aodh”
Moore — “Noble and stately”
Martin (Mac Giolla Mhártain) — “Son of the follower of St Martin”
Kane (Ó Catháin) — A modern anglicized form
Kavanagh — “Follower of St Caomhan”
Sheehan (Ó Síodhacháin) — “The peaceful one”
Foley — “Plunderer”
Kenny / Kenney (Ó Cionaoith / Ó Coinne) — “Fiery love” roots
Lillis — Listed among very Irish names in modern tallies
Burns — A widely recognized Irish surname in the diaspora
O’Reilly — Prominent across Ireland and abroad
Conclusion
If you’ve made it here, you’ve just walked a thousand years alongside poets, chiefs, monks, invaders, and emigrants—guided by nothing more than a handful of letters at the end of your first name. That’s the wonder of Irish family names. They’re part language, part map, and part love letter to everything the island has survived and created.
Irish genealogy is a pilgrimage as much as a project. Every step adds meaning. Every spelling variant is a clue. Every story you gather keeps the flame of Irish heritage and culture alive.
And if you’d like to wear that heritage with pride, explore our beautifully woven Irish tartans by family name — crafted to celebrate your roots, your clan, and your story.
Frequently Asked Questions
What is a traditional Irish last name?
Traditional Irish family names include Murphy, Kelly, O’Sullivan, Walsh, Byrne, and O’Brien. These Gaelic Irish surnames often begin with “Ó” (descendant of) or “Mac” (son of) and reflect ancestry, region, or family traits.
What are rare Irish last names?
Rare Irish surnames such as Toal (Ó Tuathail), Canavan (Ó Ceanndubháin), and Breen (Ó Braoin) are found in limited regions. Some others, like Eagleton and Berhagra, survive mainly in specific counties across Ireland.
What are the oldest Irish surnames?
The oldest recorded Irish surname is O’Clery (Ó Cléirigh), dating back to 916 AD. Other ancient names include O’Brien, O’Connor, and Murphy, all linked to Ireland’s earliest clan dynasties.
What does the O or Mac mean in Irish surnames?
In Irish family names, “Ó” means “descendant of” or “grandson of”, while “Mac” or “Mc” translates to “son of.” These prefixes show lineage in traditional Gaelic naming traditions and reflect deep clan heritage.
What is the most common Irish last name today?
According to census data, Murphy remains the most common Irish last name in Ireland. Other frequent surnames include Kelly, Byrne, O’Brien, and Walsh, many of which date back over a thousand years.
Teresa Finn
As someone with a deep passion for clan heritage, especially the intriguing world of tartans and their rich traditions, I'm here to be your companion on this exciting journey. Together, we'll delve into the depths of clan history, uncovering the stories behind these vibrant tartans and making every connection to your heritage more meaningful.
