Gaelic Surnames: A Reference Chart

Gaelic Surnames: A Complete Reference Chart

Irish and Scottish Gaelic surnames mapped across all categories — no-prefix, Mc/Mac, O', and clan-affiliated — from most common to rarest, with origins and context.

The Gaelic surname system is one of the oldest hereditary naming traditions in Europe, predating the Norman conquest by centuries. What most people encounter today as common Irish or Scottish surnames are in many cases anglicised fragments — stripped of prefixes, phonetically respelled, or outright translated — of a naming structure that once encoded lineage, territory, occupation, and clan identity directly into a person's name.

This reference charts the full landscape: names that lost their prefix and were never restored, names still carrying Mc or Mac, names holding the O' lineage marker, and the subset of all three that belong to historically recognised clans with defined territories and records.

Key Facts

Mc and Mac are the same thing Mc is simply an abbreviation of Mac. Neither spelling reliably indicates Irish vs Scottish origin. Both appear across both nations, often within the same family line across generations.

O' means "grandson/descendant of" From the Old Irish "Ua," O' names mark descent from a specific named ancestor — often a chieftain or king. Mac/Mc means "son of," making it a generation closer. Both systems were in use simultaneously.

The Great Prefix Stripping During the 18th century Gaelic submergence under English rule, most O' and Mac prefixes were dropped from daily use. O' was largely restored in the 19th century revival — Mac far less so, which is why names like Brady, Clancy, and Egan still circulate without it.

Murphy is statistically the most Irish name Murphy (from Ó Murchadha — "sea warrior") is consistently the most common surname in Ireland by population count. It originally carried the O' prefix, which was stripped and never widely restored.

Many "English" names are translated Gaelic Smith, White, Black, Brown — in Ireland and Scotland, many of these apparent English names are direct translations of Gaelic originals. Mac Gabhann (son of the blacksmith) became Smith. Mac Giolla Dhuibh (son of the black-haired lad) became Black.

Phelan and Whelan are the same name Both derive from Ó Faoláin. Regional anglicisation produced different phonetic spellings of the same Gaelic root — a pattern repeated across dozens of name pairs throughout this chart.

O'Clery may be the oldest hereditary surname in Europe The Irish surname O'Clery (Ó Cléirigh), from the word for "clerk," is considered by some scholars to be among the earliest recorded hereditary surnames in European history, predating most continental naming traditions.

MacGregor was an outlawed name The Scottish clan MacGregor had their name legally banned by the Crown in 1603 following decades of conflict. Members were forced to take other surnames. The ban was not fully lifted until 1774 — 171 years of a people forbidden from using their own name.

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Section 1

Gaelic Names — No Prefix

Fully Gaelic in origin but anglicised without Mc, Mac, or O'. Many originally carried a prefix that was stripped during the 18th century Gaelic submergence and never restored. Others are descent or territorial names that never required one.

Most Common / Widespread — Irish

Murphy

Kelly

Byrne

Ryan

Doyle

Walsh

Quinn

Gallagher

Kennedy

Lynch

Murray

Doherty

Moore

Brennan

Nolan

Connolly

Whelan

Phelan variant of Whelan / O Faoláin

Carroll

Casey

Cassidy

Clancy

Collins

Daly

Donnelly

Donovan

Dunne

Farrell

Flanagan

Kavanagh

Kearney

Sullivan O' dropped

Neill O' dropped

Shea O' dropped

Mid-Tier — Irish

Egan

Brady

Mahony

Carthy

Keogh

Boyle

Duffy

Flood

Forde

Garvey

Gorman

Hanlon

Hogan

Keane

Larkin

Malone

Molloy

Mooney

Regan

Sheridan

Tierney

Treacy

Turley

Doran

Coyle

Devlin

Sheehan

Driscoll O' dropped

Callaghan O' dropped

Toole O' dropped

Corcoran

Tully

Fagan

Carolan O' dropped

Canavan O' dropped

Scottish Gaelic — No Prefix

Cameron

Douglas

Ross

Craig

Boyd

Baird

Buchanan

Galbraith

Graham

Campbell when used without Mac

Duncan

Grant

Gordon

Munro

Drummond

Forbes

Colquhoun Mac dropped

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Section 2

Mc / Mac Names

Mac means "son of" in Gaelic. Mc is an abbreviation of the same prefix with no difference in meaning or cultural origin. Used across both Ireland and Scotland with no reliable geographic distinction between the two spellings.

Most Well-Known

McDonald / MacDonald

McCarthy / MacCarthy

McGregor / MacGregor

McKenzie / MacKenzie

McLean / MacLean

McLeod / MacLeod

McPherson / MacPherson

McNeil / MacNeil

MacArthur

MacMillan

McAllister / MacAlister

McIntosh / Mackintosh

McIntyre

McGuire / Maguire

McMahon / MacMahon

McAuley / MacAulay

McCann

McKay / MacKay

McLaughlin / MacLaughlin

McGuinness / MacGuinness

McBride

McConnell

McFarlane / MacFarlane

McRae / MacRae

McCoy

McCulloch

McGowan

McFadden

McMurray

Mid-Tier / Recognizable

MacKinnon

MacDougall

MacNab

MacFie

MacGillivray

MacQuarrie

MacLachlan

MacIver

MacBain

MacCowan

MacAndrew

MacPhail

McElroy / MacIlroy

McKenna

McGrath

McNamara

McNulty

McHugh

McGee

McSweeney

McCormack

McKiernan

McGinley

McCloskey

McAteer

McGlynn

McKeown

McCaffrey

McShane

McSorley

McQuillan

McVeigh

McElhone

Lesser Known / Rarer

MacVitie

MacVaxter

MacBratney

MacCavity

MacClery

MacVicker

MacBrayne

MacColquhoun

McGirr

MacSheehey

McSloy

MacWard

MacBard

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Section 3

O' Names

O' derives from the Old Irish "Ua" meaning grandson or descendant. Primarily Irish, these names mark descent from a specific named ancestor — typically a chieftain, king, or founder figure. Many had the prefix stripped during the English colonial period and only partially restored during the 19th century Gaelic revival.

Most Well-Known

O'Brien

O'Neill

O'Sullivan

O'Connor

O'Reilly

O'Donnell

O'Callaghan

O'Donoghue

O'Mahony

O'Rourke

O'Malley

O'Shea

O'Dwyer

O'Leary

O'Keefe

O'Toole

O'Boyle

O'Doherty

O'Flaherty

O'Gorman

O'Halloran

O'Hara

O'Meara

O'Grady

Mid-Tier

O'Farrell

O'Loughlin

O'Driscoll

O'Gara

O'Hanlon

O'Crowley

O'Molony

O'Morchoe

O'Dea

O'Corr

O'Cooney

O'Clery

O'Carolan

O'Cannon

O'Canny

O'Carbery

O'Carmody

O'Canavan

O'Madden

O'Mulrian

O'Byrne

O'Carroll

O'Kelly

Rarer / Ancient Forms

O'Conluain

O'Conaing became Gunning

O'Ciardha became Keary

O'Cadhla became Kealy

O'Caomhanach

O'Cinneide pre-Kennedy form

O'Cuinn pre-Quinn form

O'Cearbhaill pre-Carroll form

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Section 4

Clan-Affiliated Names

Names from Sections 1–3 that belong to recognised ancient clans — Irish and Scottish — with their territorial seat or historical role noted. Irish clans predate the formal Scottish clan system and operated through a different but parallel structure of kingship and sept loyalty.

Irish Clans

O'NeillKings of Tyrone / Ulster — descended from Niall of the Nine Hostages

O'BrienHigh Kings of Munster — dynasty of Brian Boru

O'ConnorKings of Connacht — provided several High Kings of Ireland

O'SullivanLords of Munster — originally lords of Cahir, Tipperary

O'DonnellLords of Tyrconnell (Donegal) — rivals and allies of the O'Neills

O'RourkeChiefs of Breifne — County Leitrim

O'ReillyChiefs of East Breifne — County Cavan

O'MalleySea-lords of Mayo — home of Gráinne Mhaol (Grace O'Malley)

O'FlahertyLords of West Connacht

O'KellyLords of Uí Maine — Galway / Roscommon

MacGuinnessLords of Iveagh — County Down

MacMahonLords of Oriel — County Monaghan

McCarthyKings of Desmond / Munster

KavanaghKings of Leinster lineage — Wexford / Carlow

O'ByrneChiefs of Wicklow / Kildare — resisted Norman rule for centuries

O'TooleAllied chiefs — County Wicklow; longtime allies of the O'Byrnes

O'DohertyLords of Inishowen — County Donegal

O'BoyleChiefs of Donegal

O'CallaghanMunster clan — County Cork

O'CarrollKings of Oriel / Ely — County Offaly / Tipperary

O'MaddenUí Maine sept — County Galway

McQuillanLords of North Antrim — associated with Dunluce Castle

Scottish Clans

MacDonaldLords of the Isles — largest Scottish clan

CampbellDukes of Argyll — most politically powerful Scottish clan

MacLeodLords of Skye and Harris — two branches, Dunvegan and Lewis

MacKenzieEarls of Seaforth — Kintail and Eilean Donan

CameronLochaber — Fort William region

MacGregorTrossachs — the outlawed clan; name banned 1603–1774

FraserBeauly / Inverness — Highland clan

MacLeanIsle of Mull

MackintoshClan Chattan confederation — Inverness

MacPhersonClan Chattan — descended from the Parson

MacGillivrayClan Chattan — Gaelic devotional naming tradition

MacDougallLords of Lorn — Argyll

MacNeilIsle of Barra — traced to Niall of the Nine Hostages

MacFieIsle of Colonsay

MacNabBreadalbane — descended from the Abbot

MacRaeKintail — hereditary constables of Eilean Donan

GunnCaithness / Sutherland — far north Scotland

MacQuarrieIsle of Ulva

BuchananLoch Lomond — Gaelic origin, Mac prefix absorbed

BoydAyrshire — from Gaelic "buidhe" (fair/yellow)

BairdLanarkshire — from Mac a' Bhàird (son of the bard)

MunroEaster Ross — migrated from Derry in the 11th century

DouglasFrom Dubhghlas (dark water) — powerful Lowland clan

On the loss and partial return of prefixes: The Mac prefix has never been restored to Irish names at the same rate as O'. Names like Brady, Clancy, Egan, Keogh, and Mahony all originally carried Mac but circulate today without it — their bearers having become so accustomed to the stripped form that reattaching the prefix made the name feel foreign. O' fared better during the 19th century Gaelic revival, though even there the restoration was uneven. The result is a surname landscape where the same ancestral root can appear in three or four visible forms simultaneously — O'Sullivan, Sullivan, Mac Suileabháin — all descending from the same stock.