An Irish surname can point to a place on the map. In 1890, nearly four out of every five Sullivan births in Ireland were registered in just two counties, Cork and Kerry, and most of the common Irish names cluster in the same way. Here are fourteen of them, province by province, and three things a surname cannot tell you.
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Where the figures come from
Our guide is an official report. Robert Matheson, of the General Register Office in Dublin, took the index of births registered in Ireland in 1890 and counted the surnames, county by county. For each name he gave the number of births, and from that an estimate of how many people carried it, in a country of about 4.7 million. His Special Report on Surnames in Ireland was published in 1894.
The meanings and family histories below come from one standard reference, Rev. Patrick Woulfe’s Irish Names and Surnames (1923). Where the meaning of a name is debated, we leave it out.
Munster
Sullivan (Ó Súileabháin)
Rank 3 in Ireland; 975 births in 1890 counting O’Sullivan. Cork had 418 Sullivan births and Kerry 349: nearly four in every five. It was the most common name in both counties.
One standard reference places the early O’Sullivans beside the River Suir in Tipperary, before they were pushed south-west into the mountains of Cork and Kerry.
McCarthy (Mac Cárthaigh)
Rank 13; 498 births. The report says more than one half were found in County Cork, with Kerry and Limerick next, and hardly any outside Munster.
The old personal name behind it means loving. The McCarthys were kings of Desmond, the old south Munster, and were driven from Tipperary into Cork and Kerry.
Ryan (Ó Maoilriain)
Rank 8; 715 births. Tipperary had, in the report’s words, “by far the largest number”: 277 births, with Limerick next at 91.
A caution: the same reference lists a separate Ryan family from County Carlow, and in English the two names look the same.
O’Brien (Ó Briain)
Rank 6; 748 births counting Brien. The report says every county in Munster is “largely represented”. In 1890 there were 139 births in Cork, 78 in Limerick, 74 in Tipperary and 47 in Clare.
O’Brien means descendant of Brian: Brian Boru, king of Ireland, whose family ruled County Clare and the land around it. Yet by 1890 Clare had fewer O’Brien births than Cork, Limerick or Tipperary. Families move.
Leinster
Murphy (Ó Murchadha)
Rank 1: an estimated 62,600 people in 1890. Murphy was the top name in only three counties: Wexford, Carlow and Armagh. But the largest number of Murphys were in County Cork: 390 births, almost three times as many as Wexford’s 137.
The name means descendant of a sea warrior, and the same reference counts several unrelated Murphy families.
Byrne (Ó Broin)
Rank 7; 734 births, 583 of them in Leinster. Byrne was the top name in Dublin, Wicklow and Louth. County Dublin had 301 births and Wicklow 87.
It means descendant of Bran, a name meaning raven. The family were driven from Kildare into the Wicklow mountains.
Doyle (Ó Dubhghaill)
Rank 12; 514 births. Three quarters of the Doyles were in six counties, led by Dublin and Wexford.
The Irish name means the dark foreigner, and one standard reference links it to the old Danish settlements on the coast. That is a clue, not proof of a Viking in your family.
Connacht
Kelly (Ó Ceallaigh)
Rank 2; found in every county. Kelly was the top name in Galway, with 119 births, and in Roscommon, where one Kelly family held power for centuries.
But that reference lists nine separate Kelly families, from Derry to Cork. Galway and Roscommon are the best single guess, not a certainty.
Walsh (Breathnach)
Rank 4; 932 births. Walsh was the top name in Mayo, with 134 births, yet there were even more in Cork: 143.
Walsh is not one family. The Irish form means the Welshman, a label for newcomers who arrived from Wales with the Normans.
Ulster
Reilly (Ó Raghailligh)
Rank 11; 648 births counting O’Reilly. Reilly was the top name in Cavan, with 137 births, and in Longford (78) and Meath (53) beside it.
The O’Reillys were chiefs of the Cavan country. Riley is the same name.
Gallagher (Ó Gallchobhair)
Rank 14; 488 births. Donegal had 196 Gallagher births: two thirds of all the Gallaghers in Ulster. Mayo came second with 92.
The name means foreign help. For centuries the Gallaghers were marshals of the O’Donnell armies in Donegal.
Doherty (Ó Dochartaigh)
Rank 15; 414 births spelled Doherty. Donegal had 160 of the 414 births spelled Doherty. It was also the top name in County Derry, which the report calls Londonderry.
The O’Dohertys were lords of Inishowen, the peninsula at the very top of the map.
McLaughlin (Mac Lochlainn)
Rank 21; 391 births in both spellings. Spelled with an A, about three quarters were in Antrim, Donegal and Derry. Spelled with an O, McLoughlin, it was mostly in Dublin and Connacht.
Behind the two spellings are two different families, one from Inishowen and one from Meath.
O’Neill (Ó Néill)
Rank 10; 651 births counting Neill. Half of the O’Neills were in Dublin, Antrim, Cork and Tyrone, and only about a third were in Ulster at all.
The Ulster O’Neills were chiefs of Tyrone, a county whose very name comes from their ancestor. There were separate O’Neill families in Clare, in Carlow and in Tipperary.
The fourteen names at a glance
| Name | Province | Where it clustered in 1890 |
|---|---|---|
| Sullivan | Munster | Cork 418, Kerry 349, of 975 in Ireland |
| McCarthy | Munster | More than half in Cork |
| Ryan | Munster | Tipperary 277, Limerick 91 |
| O’Brien | Munster | Cork 139, Limerick 78, Tipperary 74, Clare 47 |
| Murphy | Leinster | Top in Wexford, Carlow and Armagh; most in Cork (390) |
| Byrne | Leinster | Dublin 301, Wicklow 87 |
| Doyle | Leinster | Three quarters in six counties, led by Dublin and Wexford |
| Kelly | Connacht | Top in Galway (119) and Roscommon; every county |
| Walsh | Connacht | Cork 143, Mayo 134 |
| Reilly | Ulster | Cavan 137, Longford 78, Meath 53 |
| Gallagher | Ulster | Donegal 196, Mayo 92 |
| Doherty | Ulster | Donegal 160 of 414; top in Derry |
| McLaughlin | Ulster | About three quarters in Antrim, Donegal and Derry |
| O’Neill | Ulster | Half in Dublin, Antrim, Cork and Tyrone |
Three things a surname cannot tell you
1. The county, for certain
Even for Sullivan, about one birth in five was somewhere else. Cities pull names in, too: Dublin is at or near the top for Byrne, Kelly, Doyle and O’Neill. And this is one year of births, counted in registration districts that only roughly match the counties.
2. Which family
One English spelling can hide different Irish families, as with Ryan, Kelly and McLoughlin. For Moore and for Lynch, one standard reference gives both an Irish origin and a Norman one.
3. How it was spelled before
Spellings changed. In 1890, Sullivans without the O outnumbered O’Sullivans six to one. So search every spelling.
A surname is a clue. The proof is in the records: a birth, a marriage, a census page.
Still Murphy
One thing has not changed. For babies born in Ireland in 2025, the three most common surnames were Murphy, Kelly and O’Brien, according to the Central Statistics Office.
General information about surnames, not proof of any one family’s origin. Figures checked against the 1894 report on 13 October 2026.
Sources
- Robert E. Matheson, Special Report on Surnames in Ireland (1894), General Register Office, Dublin
- Rev. Patrick Woulfe, Sloinnte Gaedheal is Gall: Irish Names and Surnames (1923)
- Central Statistics Office: Irish Babies’ Names 2025
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Picture credits for the video
Every clip, photograph, map and page in the video is real, from Pexels, Wikimedia Commons, the National Library of Ireland, the Love Ireland licensed library or the 1894 report itself.
Video clips
- Dingle-1012716, Co. Kerry, Ireland, Maoileann, CC BY-SA 4.0
- Aerial view of cobh cathedral and waterfront, Clément Proust, Pexels License
- Mount Brandon-1012259, Dingle Peninsula, Co. Kerry, Ireland, Maoileann, CC BY-SA 4.0
- Aerial drone view of galley head lighthouse ireland, Clément Proust, Pexels License
- Serene swan gliding on killarney lake, Maurice Supple, Pexels License
- Majestic aerial views of rock of cashel ireland, Jay’s Photography, Pexels License
- Majestic view of cliffs of moher, Oleksandr Kobuta, Pexels License
- Scenic aerial view of inistioge ireland village, Jay’s Photography, Pexels License
- Aerial view of hook lighthouse on rocky coast, Peter Leahy, Pexels License
- Aerial view of river lee in cork city, Maurice Supple, Pexels License
- Historic church in glendalough ireland, Fernando Sánchez Aranguren, Pexels License
- Sunny day view of o connell street dublin, Maurice Supple, Pexels License
- Drone footage of marram grass on north bull island, Luciann Photography, Pexels License
- Aerial view of kylemore abbey, Andrew Mulleady, Pexels License
- Lough key castle, Andrew Mulleady, Pexels License
- Stunning aerial view of donegal castle ireland, Ravenswood Photography, Pexels License
- Drone footage of bunagee pier in culdaff ireland, Peter Steele, Pexels License
- Vibrant dublin street scene in daylight, Selim Karadayı, Pexels License
- Bustling day on historic cobblestone street, William Gevorg Urban, Pexels License
- A poet searching in a book, KoolShooters, Pexels License
- Mom kisses baby while walking with dad, Kampus Production, Pexels License
- Drone view of abandoned stone structure in ireland, Jay’s Photography, Pexels License
- Stunning aerial view of the irish coastline, Clément Proust, Pexels License
Photographs
- Cheaper by the dozen – Flickr – National Library of Ireland on The Commons, National Library of Ireland on The Commons, No restrictions
- Hugh Lane Gallery Dublin, Rwxrwxrwx, CC BY-SA 4.0
- Earl Street, Dublin (6305050889), National Library of Ireland on The Commons, No restrictions
- Patrick Street, Cork from Daunt’s Square (5823913788), National Library of Ireland on The Commons, No restrictions
- Eyre Square, Galway City (5785190759), National Library of Ireland on The Commons, No restrictions
- River Suir from Cahir Castle, Sebb, Public domain
- Wexford – Commercial Quay – geograph.org.uk – 7930553, Colin Park, CC BY-SA 2.0
- Lough Oughter, Cavan, NTF30, CC BY-SA 4.0
- Killykeen Lough Oughter-1, NTF30, CC BY-SA 4.0
- Remains of the Knox Hannynton mansion, which replaced the medieval Chichester castle, Hill of the O’Neill, Rena Maguire, CC BY-SA 4.0
- Mary Finnegan (1832-1904) in the 1901 Ireland census living in Coolaspuddaun, form A, AnonymousUnknown author, Public domain
- Bridget Conboy (born 1841) Carr in the 1901 Ireland census living in Hollygrove, form A, AnonymousUnknown author, Public domain
- 11 photographs from the Love Ireland licensed library (licensed for commercial use; no credit required).
Maps and pages
- County maps drawn by Love Ireland from boundary data: © Tailte Éireann, CC BY 4.0; © Ordnance Survey of Northern Ireland, Open Government Licence v3.0
- Pages of Matheson, Special Report on Surnames in Ireland (1894), scanned by the Internet Archive from the Cornell University Library copy; public domain
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