surnames.ie

Irish surname · 51st most common in 1911

O'Callaghan

Also spelt Callaghan

O'Callaghan is the English form of Ó Ceallacháin, 'descendant of Ceallachán'. The family descends from Ceallachán Caisil, a 10th-century king of Munster, and held lands along the Blackwater west of Mallow in Co. Cork until the Cromwellian confiscations, when its chief was transplanted to Clare.

Irish Ó CeallacháinIrish Ó Céileacháin
1901 census
10,991
#52 · 25 per 10,000
1911 census
10,997
#51 · 25 per 10,000
1926 census
10,086
#38 · 34 per 10,000
Most numerous
Cork
Highest share: Cork

Language & meaning

Meaning & Irish forms

Gaelic Gaelic Irish: a branch of the royal Eóganacht Chaisil of Munster, kin to the MacCarthys, with smaller unrelated families of similar name in Mayo and Ulster.[1][2][3]

Ó Ceallacháin
“descendant of Ceallachán”[1][4]
The Munster name, and the source of most O'Callaghans and Callaghans.
Ó Céileacháin
“descendant of Céileachán”[5][4]
A separate Ulster name, from a diminutive of Céile. Woulfe says it should be kept distinct from Ó Ceallacháin, though it was sometimes anglicised as O'Callaghan or Callaghan.

The name is built on the personal name Ceallachán, usually explained as “a diminutive of Ceallach”. Sources differ on the meaning of Ceallach: Wikipedia's O'Callaghan article connects it with a word for 'contention' and also says it means 'bright-headed'.[1][4]

Pronunciation

O'Callaghan: oh-KAL-a-han

Place

Where the O'Callaghans lived

How common the name was in each county, as a share of the population, in the three surviving full censuses of Ireland. Use the buttons to compare years.

Donegal: 35.9 per 10,000 (606 people) Waterford: 19.8 per 10,000 (163 people) Dublin: 17.3 per 10,000 (829 people) Kilkenny: 6.3 per 10,000 (47 people) Carlow: 5 per 10,000 (18 people) Limerick: 32.7 per 10,000 (469 people) Louth: 37.6 per 10,000 (237 people) Tipperary: 14.2 per 10,000 (216 people) Roscommon: 28.7 per 10,000 (270 people) Meath: 35.3 per 10,000 (230 people) Wicklow: 7.2 per 10,000 (44 people) Cavan: 19.5 per 10,000 (178 people) Cork: 114.8 per 10,000 (4,514 people) Clare: 25.5 per 10,000 (266 people) Galway: 5.4 per 10,000 (98 people) Mayo: 27.2 per 10,000 (522 people) Sligo: 22.1 per 10,000 (175 people) Leitrim: 9.5 per 10,000 (60 people) Offaly: 11.2 per 10,000 (64 people) Laois: 11.3 per 10,000 (62 people) Kildare: 10.3 per 10,000 (69 people) Kerry: 39.9 per 10,000 (637 people) Monaghan: 15.5 per 10,000 (111 people) Wexford: 9 per 10,000 (92 people) Longford: 11 per 10,000 (48 people) Westmeath: 12.5 per 10,000 (75 people) Tyrone: 4.6 per 10,000 (65 people) Antrim: 3.2 per 10,000 (153 people) Armagh: 31.8 per 10,000 (380 people) Fermanagh: 16 per 10,000 (97 people) Londonderry: 9 per 10,000 (126 people) Down: 2.5 per 10,000 (76 people)
fewerup to 121 per 10,000

Share of each county's census population. 1926 covers the 26 counties of the Irish Free State only.

Highest concentration · 1911

Cork

115 per 10,000

4,514 O'Callaghans · 4.58× the national share

Highest share, 1911

  1. Cork 115
  2. Kerry 40
  3. Louth 38
  4. Donegal 36
  5. Meath 35
  6. Limerick 33
  7. Armagh 32
  8. Roscommon 29

Per 10,000 residents. A concentration index above 1 means the name was commoner there than nationally.

County figures as a table
County190119111926Per 10k 1901Per 10k 1911Per 10k 1926
Antrim118153—33—
Armagh365380—2932—
Carlow251830759
Cavan171178134182016
Clare225266227202624
Cork4,5664,5144,407114115121
Donegal547606605323640
Down10576—43—
Dublin743829992171720
Fermanagh10697—1616—
Galway8198131458
Kerry766637670464045
Kildare766981121014
Kilkenny584736865
Laois53625591111
Leitrim666062101011
Limerick460469487313335
Londonderry102126—79—
Longford4248369119
Louth235237261363842
Mayo516522484262728
Meath208230217303535
Monaghan149111115201618
Offaly54646691113
Roscommon324270232322928
Sligo168175153212222
Tipperary225216250141418
Tyrone5265—45—
Waterford172163152202020
Westmeath787588131316
Wexford919274998
Wicklow444441777

Local strongholds in 1911

District Electoral Divisions (300+ residents) where O'Callaghans made up the largest share of the population. In Tawnawully, Co. Donegal, about one resident in 10 was a O'Callaghan.

DEDCountyO'CallaghansShare
TawnawullyDonegal69 10.3%
GlanloughKerry48 9.5%
GowlaneCork99 8.7%
ClonmeenCork29 8.1%
GlenagannonDonegal55 8.1%
TincooraCork41 7.4%
RosnaleeCork30 6.8%
LowertownCork31 6.6%

Origins

Septs & territories

Many Irish surnames were adopted independently by unrelated families. These are the distinct O'Callaghan lineages described in the sources.

A surname can point you towards a place. On its own, it cannot establish a pedigree.

Ó Ceallacháin of Cineál Aodha and Pobal Uí Cheallacháin

Cineál Aodha (the barony of Kinalea), then the Blackwater valley west of Mallow, including the parishes of Kilshannig and Clonmeen · Cork

The main family, descended from Ceallachán Caisil. Woulfe says they were first chiefs of Cineál Aodha in south Cork, were driven out after the Anglo-Norman invasion and resettled on the Blackwater, where their lands were called Pobal Uí Cheallacháin. Burke places the sept in the barony of Duhallow and calls them of the same race as the MacCarthys.[1][3]

Ó Ceallacháin of Erris

Erris · Mayo

Woulfe records a Mayo family of the name, a branch of the Uí Fiachrach, who were lords of Erris in early times.[1]

Ó Céileacháin of Uí Breasail

Uí Breasail, on the southern shore of Lough Neagh · Armagh, Louth, Meath, Monaghan

A distinct Ulster family whom Woulfe describes as ancient chiefs of Uí Breasail in Co. Armagh. Wikipedia adds that the Annals of the Four Masters record them as lords there and as priors of Armagh in the 11th century, and that in Meath the name is often anglicised Callaghan.[5][4]

The name over time

History

Ceallachán of Cashel

The O'Callaghans take their descent from Ceallachán Caisil, king of Munster in the mid-10th century and a member of the Eóganacht Chaisil, the Cashel branch of the Eóganachta. Wikipedia dates his reign to about 944–954, while its O'Callaghan article gives 935–954. He first appears in the record attacking Clonmacnoise in 936, was captured in 941 and held for some years at the court of the high king Donnchad Donn, and in 944 defeated Cennétig mac Lorcáin, father of Brian Boru. He died in 954. A later saga, Caithréim Chellacháin Chaisil, presents him as a champion against the Norse.[2][4]

Named from a later Ceallachán

Woulfe points out that the surname was not formed from the king himself but from a namesake four generations later. Wikipedia's account of the king's descendants shows how the family fits in: among the sons of his son Donnchad were Saorbhreathach, from whom the MacCarthys descend, and Murchadh, described as forefather of the O'Callaghans. The two families were therefore close kin, which is why Burke describes the O'Callaghans as being of the same race as the MacCarthys. Both were part of the ruling Eóganacht stock of Munster.[1][2][3]

From Kinalea to the Blackwater

According to Woulfe, the O'Callaghans were first chiefs of Cineál Aodha in south Cork, the district later known as the barony of Kinalea. Soon after the Anglo-Norman invasion Robert FitzStephen and Milo de Cogan drove them out, and they moved north-west to the banks of the River Blackwater, west of Mallow. There they built up a substantial territory known as Pobal Uí Cheallacháin, 'O'Callaghan's country', covering the parishes of Kilshannig and Clonmeen. Burke places this sept in the barony of Duhallow, the north-western barony of the county through which the Blackwater flows.[1][3][6]

Cromwell and Clare

The O'Callaghans held their Blackwater lands until the Cromwellian confiscations. Woulfe and Burke both record that the head of the family was then transplanted to Co. Clare. Wikipedia says the family lost its ancestral home and some 24,000 acres and settled in east Clare. Land near Mallow forfeited by Donough O'Callaghan after the 1641 rising passed to the Longfield family, who later built Longueville House there. In the 20th century a descendant of Donough bought Longueville, returning about 500 acres to O'Callaghan ownership.[1][3][4]

Abroad and at home

Like many dispossessed Gaelic families, some O'Callaghans served in continental armies. Burke records arms allowed in 1765 to James Louis O'Callaghan of Baden-Baden, son of John O'Callaghan, a captain in O'Brien's regiment in the French service who died in 1712. In Ireland the name rose again in the peerage: Burke records the arms of the Viscounts Lismore and of the O'Callaghans of Cadogan, Co. Cork. In the 19th century John Cornelius O'Callaghan wrote a history of the Irish brigades in France, and Edmund Bailey O'Callaghan became a political leader in Quebec.[3][7][4]

Other Callaghans

Not every Callaghan descends from the Munster family. Woulfe records a separate Ó Ceallacháin family in Mayo, lords of Erris and a branch of the Uí Fiachrach. In Ulster the unrelated Ó Céileacháin, chiefs of Uí Breasail in Armagh, were sometimes anglicised as O'Callaghan or Callaghan, especially in Co. Meath, though the name also appears as Kellaghan and Keelan. Some families simply adopted the name: the father of the British prime minister James Callaghan was born Garoghan and changed his surname on joining the Royal Navy.[1][5][4][8]

Places linked to the name

  • Duhallow (Dúiche Ealla), Co. Cork — North-west Cork barony where Burke places the O'Callaghan sept.[3][6]
  • Clonmeen and Kilshannig, Co. Cork — Parishes on the Blackwater west of Mallow that made up Pobal Uí Cheallacháin; Burke records O'Callaghan of Clonmeen.[1][3]
  • Kinalea (Cineál Aodha), Co. Cork — South Cork barony where the O'Callaghans were chiefs before the Anglo-Norman invasion.[1]
  • Longueville House, near Mallow, Co. Cork — Built on land forfeited by Donough O'Callaghan after 1641 and bought back by a descendant in the 20th century.[4]
  • Erris, Co. Mayo — District whose early lords included a separate Ó Ceallacháin family of the Uí Fiachrach.[1]

Everyday lives

The O'Callaghans in the census

Who the O'Callaghans were in the 1901 and 1911 censuses (and 1926 where recorded), set against everyone in Ireland in the same census.

O'Callaghans All of Ireland Ireland's figure marked on the O'Callaghan bar

Religion, 1911

Catholic +23.2 points vs Ireland
O'Callaghans 96.8%
All of Ireland 73.6%
Church of Ireland −11.1 points vs Ireland
O'Callaghans 2.1%
All of Ireland 13.2%
Presbyterian −9.6 points vs Ireland
O'Callaghans 0.5%
All of Ireland 10.1%
Methodist & other −2.4 points vs Ireland
O'Callaghans 0.7%
All of Ireland 3.1%

Irish language

Spoke Irish, 1901 +5.8 points vs Ireland
O'Callaghans 21.1%
All of Ireland 15.3%
Spoke Irish, 1911 +3.8 points vs Ireland
O'Callaghans 17.3%
All of Ireland 13.5%
Spoke Irish, 1926 · 26 counties −0.7 points vs Ireland
O'Callaghans 12.8%
All of Ireland 13.5%

35 O'Callaghans spoke Irish only in 1901.

Reading & writing

Could read and write, 1901 · aged 15+ −1.0 points vs Ireland
O'Callaghans 79.4%
All of Ireland 80.4%
Could read and write, 1911 · aged 15+ −1.0 points vs Ireland
O'Callaghans 84.8%
All of Ireland 85.8%

Family life, 1911

Household size · 2,292 households about the same as Ireland
O'Callaghans 4.79
All of Ireland 4.83
Children born per mother · women 45–59 higher than Ireland
O'Callaghans 6.79
All of Ireland 6.46
Children still living about the same as Ireland
O'Callaghans 79.7%
All of Ireland 79.8%

Commonest occupations

Adults aged 15+, 1901 and 1911 combined.

Farmer1,920
Farmer's son978
Farmer's daughter479
Agricultural labourer404
General labourer385
Labourer322
Farm servant314
House keeper267
Farm labourer207
Housekeeper183

Born outside Ireland

1.2% of O'Callaghans in 1911 gave a birthplace outside Ireland.

England73
Scotland32
United States16
India5
Wales4

Median age: 24 in 1901, 26 in 1911.

Given names

First names among the O'Callaghans

Men and boys

  1. John2,372
  2. Patrick1,618
  3. Michael1,322
  4. James1,132
  5. Thomas893
  6. Daniel734
  7. William585
  8. Denis585
  9. Timothy551
  10. Jeremiah462

Women and girls

  1. Mary2,663
  2. Margaret1,038
  3. Bridget982
  4. Ellen929
  5. Kate609
  6. Catherine563
  7. Julia505
  8. Annie453
  9. Hannah414
  10. Anne337

All three censuses combined. Top five in 1926: John, Patrick, Michael, James, Thomas; Mary, Margaret, Bridget, Ellen, Kate.

Spellings

Spellings

This page combines the spellings below, which census enumerators and families used for the same name.

Spelling190119111926Records
Callaghan7,5597,1605,293Search
O'Callaghan3,4323,8374,793Search

Related forms

  • Callaghan — The form without the Ó prefix, listed by Woulfe.[1]
  • O'Callahan, Callahan — Spellings without the 'g', listed by Woulfe.[1]
  • Calligan — A further English form of Ó Ceallacháin given by Woulfe.[1]
  • Kelaghan, Kellaghan, Keelan — Forms of the separate Ulster name Ó Céileacháin.[5][4]

Diaspora

The O'Callaghans abroad

Emigration carried the name worldwide. In the 2010 United States census:

SpellingPeopleUS rank
Callaghan6,1915614th
O'Callaghan3,01410626th

Source: US Census Bureau, 2010 surname file (public domain).

Heraldry

Is there a O'Callaghan coat of arms?

Arms were recorded for particular O'Callaghan families, not for the name as a whole. Burke gives for the sept of Duhallow a silver shield with a green mound at the base and, on the right, a grove of oak trees from which a wolf walks towards the left, all in natural colours. He records the same arms for O'Callaghan of Clonmeen and for the Viscounts Lismore, whose crest is a bare arm holding a sword with a snake twined round it, with two stags as supporters and the motto 'Fidus et audax' ('faithful and bold').[3]

Websites selling a single “O'Callaghan family crest” are selling a design, not an inheritance. Arms in Ireland belonged to individuals and their heirs, and the Chief Herald of Ireland still grants arms that way today.

People

Notable people named O'Callaghan

Questions

Questions about the O'Callaghan name

Is O'Callaghan an Irish surname?

Yes. O'Callaghan is the English form of the Gaelic Ó Ceallacháin. The main family were a branch of the royal Eóganacht of Munster, descended from the 10th-century king Ceallachán Caisil, and held lands in Co. Cork along the Blackwater until the Cromwellian confiscations.[1][2]

What is O'Callaghan in Irish?

Ó Ceallacháin, meaning 'descendant of Ceallachán', a diminutive of the personal name Ceallach. It should not be confused with Ó Céileacháin, an unrelated Armagh name that was sometimes also anglicised as Callaghan. Woulfe notes that the Munster surname was taken from a Ceallachán who lived four generations after the king Ceallachán Caisil.[1][5]

Are Callaghan, Callahan and O'Callaghan the same name?

Usually. Woulfe lists O'Callaghan, Callaghan, O'Callahan, Callahan and Calligan as English forms of Ó Ceallacháin. Some Ulster and Meath Callaghans, however, come from the unrelated Ó Céileacháin of Armagh, and occasionally the name was adopted by families of quite different origin.[1][5][4][8]

Where does the O'Callaghan name come from?

From Co. Cork. The family were first chiefs of Cineál Aodha (Kinalea) in the south of the county and, after being driven out by Anglo-Norman settlers, held Pobal Uí Cheallacháin on the Blackwater west of Mallow, in the barony of Duhallow. After the Cromwellian confiscations their chief was transplanted to Co. Clare.[1][3]

Is there an O'Callaghan family crest or motto?

There is no crest for everyone named O'Callaghan. Burke records arms for the O'Callaghan sept of Duhallow, showing a wolf coming out of an oak grove, and the same arms for the Viscounts Lismore, whose motto was 'Fidus et audax', 'faithful and bold'. The motto belongs to that peerage family, not to the name generally.[3]

Are the O'Callaghans related to the MacCarthys?

Yes, according to the genealogies. The grandsons of Ceallachán Caisil through his son Donnchad included Saorbhreathach, ancestor of the MacCarthys, and Murchadh, ancestor of the O'Callaghans. Burke accordingly describes the O'Callaghans as of the same race as the MacCarthys, and both families belonged to the Eóganacht Chaisil of Munster.[2][3]

Where in Ireland is the O'Callaghan surname most common?

In the 1911 census the largest numbers of O'Callaghans lived in Cork (4,514), Dublin (829), Kerry (637). Relative to population, the name was most concentrated in Cork (115 per 10,000), Kerry (40 per 10,000), Louth (38 per 10,000).

How common was the O'Callaghan surname in Ireland?

10,997 people were recorded as Callaghan or O'Callaghan in the 1911 census of Ireland, making it the 51st most common surname. That is roughly 0.3% of the population, or 1 person in 400.

Looking for a O'Callaghan ancestor?

Search every O'Callaghan household in the 1901, 1911 and 1926 censuses, with free images of the original forms.

Search records on irishcensus.com

Evidence

Sources

  1. Patrick Woulfe, Ó Ceallacháin, in Irish Names and Surnames (1923)
  2. Wikipedia, Cellachán Caisil (2026)
  3. Sir Bernard Burke, The General Armory of England, Scotland, Ireland, and Wales (1884). Entries 'O'Callaghan' (Duhallow sept, Clonmeen, Viscount Lismore, Cadogan, Baden-Baden).
  4. Wikipedia, O'Callaghan (2026)
  5. Patrick Woulfe, Ó Céileacháin, in Irish Names and Surnames (1923)
  6. Wikipedia, Duhallow (2026)
  7. Wikipedia, John Cornelius O'Callaghan (2026)
  8. Wikipedia, James Callaghan (2026)
  9. Census of Ireland 1901 and 1911, and Census of Population 1926, National Archives of Ireland. Counts compiled by surnames.ie from the irishcensus.com transcription (dataset 20260831130351). 1926 data © National Archives of Ireland, CC BY 4.0.
  10. Irish forms cross-checked against Gaois surname data (Fiontar & Scoil na Gaeilge, DCU).

How we compile these figures: methodology.