Top 20 Irish surnames

Griffith's Valuation recorded 11,518 Kellys and only 57 O'Kellys. Most were in Galway (986), Roscommon (815) and Mayo (595). Ulster had 2,640 Kelly entries, but only 65 were in Fermanagh.

A total population of Kellys was estimated at 55,900 in 1890. The name appeared in all counties but was  most common in Cork, Galway, Mayo, Dublin, Roscommon.

Meaning, Origin, and Miscellaneous information: The derivation of the name is not certain. It may have come from ceallach, meaning 'strife'. In Irish, the name is written O'Ceallaigh. Originally only a surname, it became first a boy's first name and, later, a girl's name.

Of the 8,000 O'Sullivan or Sullivan households recorded in Griffith's Valuation in the middle of the 19th-century, nearly three-quarters were in Cork (3388) or Kerry (2567). Some 15 counties had less than 20 households with this name.

Little had changed by 1890, when some 90% of O'Sullivans were estimated to be in Munster.

Meaning, Origin, and Miscellaneous information: Internationally recognised as one of the great Irish surnames, O'Suileabhan, meaning 'hawk-eyed' or 'one-eyed', remains the most common name in counties Cork and Kerry. In 1992-97 there were approx 41,500 telephone subscribers of this name across the island of Ireland*.

In 2020, an analysis by the Republic's Central Statistical Office of the family names of children whose births were registered in the previous year found the 348 newly-arrived O'Sullivans made it the eighth most common surname. 

Of the 9,843 households named Walsh/e, Welsh, Welch or Brannagh who appear in Griffith's Valuation (1847-1864), the largest clusters were found in counties Kilkenny (1,420), Cork (1,357) and Mayo (1,092).

The name was most common in Galway, Dublin, Wexford, Cork and Mayo. Numbers were lowest in Ulster.

Meaning, Origin, and Miscellaneous information: The name was originally Breatnach, meaning 'from Wales', which arrived in Ireland with the Norman invaders. The name is usually pronounced 'Welsh; in Munster and Connacht.

An analysis by the Republic's Central Statistical Office of the family names of children whose births were registered in 2020 found the 383 newly-arrived Walsh's and the seventh most common surname for that year.

Scattered across the island, Smith households were most numerous in Counties Cavan (1,074), Down (635) and Meath (578).

More than half the Smiths were in Ulster, and more than one quarter in Leinster.

Meaning, Origin, and Miscellaneous information: Although England's most common surname, Smith in Ireland does not necessarily suggest an English ancestry. Many MacGowans (whose name derives from gabhann, meaning 'smith' ie blacksmith) had their name translated into English 300 to 400 years ago.

In 2020, the Republic's Central Statistics Office analysed the surnames of babies born and registered during the previous year. Surprisingly, Smith did not make it into the top 10.

By far the most prevalent county for Byrne households in the mid-19th century was Wicklow where it was recorded 1203 times. The neighbouring counties of Dublin (893), Carlow (572) and Wexford (534) were the next largest concentrations. The smallest numbers were found in Derry (9).

Leinster was the great stronghold of this name, with five times more Byrnes than the other three provinces combined. More than half (301) of the 568 Byrne births in 1890 were in Co. Dublin; 87 were in Co Wicklow.

Meaning, Origin, and Miscellaneous information: O'Broin, meaning raven, can be traced back to Bran, the son of an 11th-century king of Leinster. It remains one of the most common Irish surnames in Wicklow and neighbouring counties, and in 2020 was the fifth most common surname to appear in the civil registration of births registers (up from seventh the year before).

There were 8,871 Ryan households recorded in Griffith's Valuation (a survey carried out across the island between 1847 and 1864). Nearly half (4,090) were in Tipperary.  Limerick had 1,263 while the next most numerous were counties Kilkenny (616) and Cork (409).

In 1890, more than half of all Ryan births were in Munster, especially counties Tipperary, and then Limerick. There were only 13 entries in all of Ulster, and just 49 in Connacht.

Meaning, Origin, and Miscellaneous information:  In Old Irish, the name was spelt O'Mulriain; in Modern Irish, it's O'Riain. It's long been the most numerous of Irish surnames in Tipperary, and has become a popular first name. It means 'little king', and the sept of this name was from the Tipperary/Limerick borders.

In 2020, the Republic's Central Statistics Office found the family name Ryan took third place in its Top 10 Surnames of Babies Registered from January to December of that year (by number).

Take a more detailed look at the Irish surname Ryan.

In the mid-19th century, the singular form of Connor was the most numerous of varients for this name, with 5,377 households being found mainly in Kerry and Cork. There were also 1,749 using the plural form Connors (especially in Wexford and Waterford). Those households using the name O'Connor numbered only 841 and were mainly in Munster.

Of 266 Connor/O'Connor births in 1890, 80% were in Kerry, Cork, Limerick, Dublin, Clare and Galway. Just 13 were in Ulster.

The name comes from Conchobar, meaning 'lover of hounds', and remains very common in Kerry. The O' prefix, formerly discarded, has now resumed its position, and in an official Top 10 of Surnames of Babies Registered in 2020, took sixth place.

The Neills and O'Neills were fairly evenly split with 2578 and 2720 households respectively. Just one fifth (537) of the former and more than half (1412) of the latter were in the six counties that now make up Northern Ireland.

There were 407 O'Neill births in 1890. They covered nearly all counties but more than half were in Dublin, Antrim, Cork and Tyrone. Only 28 were in Connacht.

Meaning, Origin, and Miscellaneous information: O'Neill means descendent of Niall, a first name which means 'vehement'. The main O'Niall family, centred on Tyrone, descended from Niall of the Nine Hostages, but there were other, separate, groups in Carlow and Waterford. It's still a very big name in Ulster.

Griffith's Valuation (1847-1864) shows that by far the greatest concentration of Reilly households was in County Cavan (1759). The next largest, Meath, had only 579 examples. Reilly households outnumbered O'Reillys nearly 20-1.

County Cavan remained the stronghold of Reillys with 137 births registered in 1890. But there were 319 births elsewhere, including 93 in Dublin and 78 in Longford. Only 10% of Reillys used the O' prefix at this time.

Meaning, Origin, and Miscellaneous information: What a difference 100 years can make! By the dawn of the 21st century, almost 60% of Reillys used the O' prefix.

The name comes from raghallaigh, possibly meaning 'sociable tribe or group'. The origins of the Reillys lies in Breffny (a kingdom based across modern-day counties Cavan and Longford where it remains the most common surname).

Griffith's Valuation (a survey taken between 1847 and 1864) found there were 4,634 Doyle households recorded across Ireland. More than half were in Wexford (1,169), Wicklow (556), Carlow (393) and Dubliln (330). The smallest numbers were in the far northwest.

Of the 360-odd Doyle birth registrations in 1890, three-quarters were in Counties Dublin (162) and Wexford (102). Other 'big' Doyle counties were Kildare, Carlow and Wicklow.

Meaning, Origin, and Miscellaneous information: One of several common Irish surnames which didn't re-attach the O' prefix, the surname comes from the Irish for 'dark stranger' possibly meaning Vikings, and is not believed to have any Celtic connections.

With 2,298 households, County Cork had by far the highest proportion of the 3,830 McCarthy entries in Griffiths Valuation (1848) . There were also 1203 Carty and 534 Carthy households.

The southwest of the island remained the stronghold in 1890, with an estimated 90% of the McCarthy population in Munster. Of about 380 McCarthys, 72% were in Cork.

Meaning, Origin, and Miscellaneous information: The name means 'loving' (ahhhh), and derives from Carthach, an 11th century king of Cashel. In the 12th century the dynasty was exiled from Tipperary and relocated to Cork and Kerry. About 60% of McCarthy families hail from Cork.

Although spread wide geographically, the 4,125 Gallagher households recorded in Griffith's Valuation were most common in 1847-1864 in north western counties, especially Donegal (1,732) and Mayo (627). The smallest numbers were in Kilkenny and Tipperary (just 7 combined).

By 1890, Ulster (principally Donegal) still held the greatest number of Gallaghers, with Connacht in second place.

Meaning, Origin, and Miscellaneous information:  And little has altered into modern times. Gallagher still holds the number one spot for Irish surnames in County Donegal.

Meaning 'foreign helper', the Old Irish spelling is O'Gallchobhair; the Modern Irish Gallachoir. It has more than 20 variant spellings, and descends from a son of Niall of the Nine Hostages.

Ulster was still the the province most densely populated with Dohertys in 1890. All other provinces had only small numbers.

Meaning, Origin, and Miscellaneous information: Originally the Dohertys were one of the great families of the Inishowen peninsula, and another that's descended from Niall of the Nine Hostages, the Dohertys are still especially numerous in counties Donegal and Derry. The name means 'unlucky' and took 14th place in a 1996 survey of common Irish surnames.

Of the 4,820 Kennedy households recorded in Griffith's Valuation (1847-1864), just under a quarter (1,112) were located in County Tipperary. The remainder were scattered across the island. Limerick had 262, Antrim 258, Down 211 and Kilkenny 232.

Still widely distributed in 1890, the province with the lowest population of Kennedys was Connacht. County Tipperary saw the highest number (70) of Kennedy births, with Dublin in second place with 51.

Meaning, Origin, and Miscellaneous information: The Old Irish spelling is O'Ceanneidigh, which means 'ugly head'. This Irish surname descended from a nephew of Brian Boru. The family were Lords of Ormond throughout the early medieval period before splitting into three distinct groups and dispersing.

Matheson's Special Report

Robert R Matheson's Special Report on Surnames in Ireland was a statistical report based on the births registered in Ireland during the year 1890. As such it provides us with a snapshot of the distribution of Irish surnames in that year.

For all its obvious usefulness and interest to Irish family historians, there's an important issue to consider when exploring the most common Irish surnames.

The report was written at a time when the population of Ireland had suffered extreme changes caused by the Great Famine, huge shifts of people from the countryside to the towns and cities of the island, and mass emigration.

These changes would have been reflected in the distribution of Irish surnames. Unfortunately, we will never know just how different the data may have been if a similar survey of names had been carried out in the early years of the century.

Top Irish surnames in 2020

• According to the Central Statistics Office in the Republic of Ireland, the top ten surnames of babies registered from January to December 2020 were:

• Murphy
• Kelly
• O'Brien
• Ryan
• Byrne
• O'Connor
• Walsh
• O'Sullivan
  
• McCarthy
• Doyle

See the full statistical dataset at CSO.ie (excel file)