surnames.ie

Irish surname · 41st most common in 1911

Duffy

Also spelt Duffey, O'Duffy

Duffy, with O'Duffy and Duffey, comes from the Irish Ó Dubhthaigh, 'descendant of Dubhthach', a personal name meaning dark or black. Several unrelated families bore it, the best known being a Roscommon church family who supplied many medieval bishops in Connacht and a Monaghan sept near Clontibret.

Irish Ó Dubhthaigh · Ó DufaighIrish Ó DoitheIrish Ó Dúithche
1901 census
12,626
#41 · 29 per 10,000
1911 census
12,160
#41 · 28 per 10,000
1926 census
10,258
#37 · 35 per 10,000
Most numerous
Mayo
Highest share: Monaghan

Language & meaning

Meaning & Irish forms

Gaelic Gaelic Irish: several distinct families named Ó Dubhthaigh, joined in English by the unrelated Mayo name Ó Doithe.[1][2]

Ó Dubhthaigh
Modern spelling: Ó Dufaigh
“descendant of Dubhthach”[1][3][4][5]
Woulfe's headword. The simplified modern spelling appears in the place name Lios Ó nDufaigh (Lissonuffy) and in Louise Gavan Duffy's Irish name, Luíse Ghabhánach Ní Dhufaigh. Charles Gavan Duffy was born Cathal Gabhánach Ó Dubhthaigh.
Ó Doithe
“an old Mayo surname”[2]
A separate name, common in Mayo and Galway, which Woulfe says was always rendered Duffy in English.
Ó Dúithche
“a corrupted form of Ó Dubhthaigh”[6]
Woulfe lists it as a common corruption, anglicised Dooey or Duffy.

The name is built on the personal name Dubhthach, usually explained as “black, dark”. Woulfe and Wikipedia both gloss Dubhthach as 'black'. The name is built on dubh, 'black'.[1][7]

Pronunciation

Duffy: DUFF-ee

Place

Where the Duffys 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: 93.1 per 10,000 (1,570 people) Waterford: 1.5 per 10,000 (12 people) Dublin: 23.7 per 10,000 (1,139 people) Kilkenny: 1.3 per 10,000 (10 people) Carlow: 0.6 per 10,000 (2 people) Limerick: 3.1 per 10,000 (45 people) Louth: 98.3 per 10,000 (619 people) Tipperary: 2.5 per 10,000 (38 people) Roscommon: 62.5 per 10,000 (587 people) Meath: 56.9 per 10,000 (371 people) Wicklow: 19.2 per 10,000 (117 people) Cavan: 34 per 10,000 (311 people) Cork: 1.3 per 10,000 (53 people) Clare: 2.4 per 10,000 (25 people) Galway: 18.4 per 10,000 (336 people) Mayo: 100.8 per 10,000 (1,937 people) Sligo: 41.2 per 10,000 (326 people) Leitrim: 9 per 10,000 (57 people) Offaly: 36.9 per 10,000 (210 people) Laois: 8 per 10,000 (44 people) Kildare: 19.7 per 10,000 (132 people) Kerry: 2 per 10,000 (32 people) Monaghan: 210.1 per 10,000 (1,503 people) Wexford: 2.7 per 10,000 (28 people) Longford: 72.1 per 10,000 (316 people) Westmeath: 66.3 per 10,000 (399 people) Tyrone: 18.3 per 10,000 (262 people) Antrim: 8.9 per 10,000 (427 people) Armagh: 24.5 per 10,000 (293 people) Fermanagh: 59.3 per 10,000 (360 people) Londonderry: 27.3 per 10,000 (382 people) Down: 7.1 per 10,000 (217 people)
fewerup to 246 per 10,000

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

Highest concentration · 1911

Monaghan

210 per 10,000

1,503 Duffys · 7.59× the national share

Highest share, 1911

  1. Monaghan 210
  2. Mayo 101
  3. Louth 98
  4. Donegal 93
  5. Longford 72
  6. Westmeath 66
  7. Roscommon 63
  8. Fermanagh 59

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
Antrim361427—89—
Armagh332293—2725—
Carlow1216015
Cavan283311327293440
Clare112539124
Cork305383112
Donegal1,5851,5701,507929399
Down196217—77—
Dublin1,0981,1391,362252427
Fermanagh363360—5659—
Galway381336341201820
Kerry333225222
Kildare133132105222018
Kilkenny15107211
Laois424427785
Leitrim5857768913
Limerick464558334
Londonderry413382—2927—
Longford360316291777273
Louth6576196181019899
Mayo1,9831,9371,802100101104
Meath388371347555756
Monaghan1,8181,5031,602244210246
Offaly213210213353741
Roscommon634587511636361
Sligo316326300394142
Tipperary433847333
Tyrone246262—1618—
Waterford141226223
Westmeath435399380706667
Wexford282821332
Wicklow110117127181922

Local strongholds in 1911

District Electoral Divisions (300+ residents) where Duffys made up the largest share of the population. In Kilmovee, Co. Mayo, about one resident in 7 was a Duffy.

DEDCountyDuffysShare
KilmoveeMayo357 13.9%
GreaghMonaghan99 13.3%
CorracharraMonaghan80 12.8%
Mount HamiltonTyrone41 11.5%
AnnagaryDonegal388 11.4%
MoyneLongford103 10.9%
LaraghMonaghan98 10.6%
UrlaurMayo190 9.0%

Origins

Septs & territories

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

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

Ó Dubhthaigh of Lissonuffy

Lissonuffy, north-east Co. Roscommon, with church offices across Connacht · Roscommon, Galway, Mayo

A Connacht ecclesiastical family whose members included Muireadhach Ua Dubhthaigh, archbishop of Connacht (died 1150), and Cadla Ua Dubthaig, archbishop of Tuam from 1161 to 1201. Woulfe remarks on how many eminent prelates the Connacht O'Duffys gave to the church. Wikipedia lists bishops of Elphin, Killala, Mayo and Clonmacnoise and an abbot of Cong from the family.[8][9][1][3]

O'Duffy of Monaghan

Ballyduffy, near Clontibret · Monaghan

Woulfe calls the O'Duffys a family of note in Monaghan and found the name very common across Ulster, especially in Monaghan and Donegal. Burke records arms for O'Duffy of Ballyduffy, naming a Hugh O'Duffy buried at Clontibret in 1636 and four generations of his ancestors, and claims the family were an offshoot of the O'Rourkes.[1][10]

Ó Dubhthaigh of Munster (Duhig)

Munster

In Munster the name was generally written Duhig in English, because the final g was pronounced. Woulfe reports that Keating gave this family a Dalcassian origin.[1]

Ó Doithe of Mayo

Ballyduffy, parish of Addergoole · Mayo, Galway

An old Mayo family with a separate Irish surname, still common in Mayo and Galway in Woulfe's time but always anglicised Duffy. Their ancient residence is marked by Baile Uí Dhoithe, or Ballyduffy, in Addergoole parish.[2]

The name over time

History

A name from Dubhthach

Duffy comes from Ó Dubhthaigh, 'descendant of Dubhthach', an Old Irish personal name meaning black or dark. Because the personal name was widespread, the surname arose independently in several places. Woulfe found it in every part of Ireland and concluded that there must be several unrelated families of the name. He picked out three in particular: a Connacht family known for its churchmen, a Monaghan family of standing, and a Munster family that Keating considered Dalcassian. Wikipedia describes the name as originating in Connacht.[1][7]

Bishops of Connacht

The best-documented medieval Duffys were a church family from Lissonuffy, Lios Ó nDufaigh, in north-east Roscommon. Over several centuries they produced a remarkable run of senior clergy. Wikipedia names a lector of Tuam who died in 1097, two bishops of Elphin in the 12th century, a bishop of Killala and a bishop of Mayo in the early 13th, an abbot of Cong who died in 1223 and a Franciscan bishop of Clonmacnoise in the 1290s. Cadla Ua Dubthaig was the second archbishop of Tuam, from 1161 until 1201.[8][9][3][1]

Muireadhach Ua Dubhthaigh and the Cross of Cong

The most famous of these churchmen was Muireadhach Ua Dubhthaigh, archbishop of Connacht from the 1130s, who died at Cong in 1150. His name appears in the inscription of the Cross of Cong, a jewelled processional cross made around 1123–1127 for Tairrdelbach Ua Conchobair, king of Connacht and high king of Ireland. The inscription asks for prayers for Muireadhach as the senior churchman of Ireland, and names his kinsman Domnall mac Flannacáin Ua Dubthaig, bishop of Elphin, as the man under whose supervision the cross was made. It is now in the National Museum of Ireland.[8][11]

The O'Duffys of Monaghan

Woulfe describes the O'Duffys as a family of note in Monaghan, and he found the name especially common there and in Donegal. Burke's General Armory records arms for O'Duffy of Ballyduffy in Co. Monaghan, tracing a Hugh O'Duffy, buried at Clontibret in January 1636, back through his father, grandfather and great-grandfather Owen More O'Duffy, all of the same place. Burke states that they descended from the O'Rourkes; Woulfe does not mention this. In the 20th century, Eoin O'Duffy, born Owen Duffy, led the Monaghan Brigade of the IRA.[1][10][12]

Duhig, Dowey and Black

The English spellings of Ó Dubhthaigh vary by region. In Munster it was usually written Duhig, reflecting a pronunciation with a final g. In Ulster Woulfe heard it as Dowey or Dooey, and occasionally it was translated outright as Black, from dubh. Other Irish names fed into the English Duffy too. Ó Doithe, an old Mayo and Galway surname whose seat was at Ballyduffy in Addergoole parish, was always made Duffy, and Ó Dúithche, a corrupted form, gave both Dooey and Duffy.[1][2][6]

Places linked to the name

  • Lissonuffy (Lios Ó nDufaigh), Co. Roscommon — Parish whose Irish name recalls the Uí Dhufaigh; home of the medieval church family of the name.[3][8]
  • Cong (Conga), Co. Mayo — Where Archbishop Muireadhach Ua Dubhthaigh died in 1150; a Duffy was abbot there in the early 13th century.[8]
  • Tuam (Tuaim), Co. Galway — Archiepiscopal see held by Cadla Ua Dubthaig from 1161 to 1201.[9]
  • Clontibret (Cluain Tiobrad), Co. Monaghan — Burial place of Hugh O'Duffy of Ballyduffy in 1636, according to Burke.[10]
  • Ballyduffy, Addergoole (Baile Uí Dhoithe), Co. Mayo — Site of the ancient residence of the Ó Doithe family, whose name became Duffy in English.[2]

Everyday lives

The Duffys in the census

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

Duffys All of Ireland Ireland's figure marked on the Duffy bar

Religion, 1911

Catholic +24.3 points vs Ireland
Duffys 97.9%
All of Ireland 73.6%
Church of Ireland −12.0 points vs Ireland
Duffys 1.2%
All of Ireland 13.2%
Presbyterian −9.7 points vs Ireland
Duffys 0.4%
All of Ireland 10.1%
Methodist & other −2.7 points vs Ireland
Duffys 0.4%
All of Ireland 3.1%

Irish language

Spoke Irish, 1901 +7.7 points vs Ireland
Duffys 23.0%
All of Ireland 15.3%
Spoke Irish, 1911 +7.4 points vs Ireland
Duffys 20.9%
All of Ireland 13.5%
Spoke Irish, 1926 · 26 counties +3.9 points vs Ireland
Duffys 17.4%
All of Ireland 13.5%

163 Duffys spoke Irish only in 1901.

Reading & writing

Could read and write, 1901 · aged 15+ −8.8 points vs Ireland
Duffys 71.6%
All of Ireland 80.4%
Could read and write, 1911 · aged 15+ −6.6 points vs Ireland
Duffys 79.2%
All of Ireland 85.8%

Family life, 1911

Household size · 2,514 households lower than Ireland
Duffys 4.69
All of Ireland 4.83
Children born per mother · women 45–59 higher than Ireland
Duffys 6.6
All of Ireland 6.46
Children still living +2.1 points vs Ireland
Duffys 81.9%
All of Ireland 79.8%

Commonest occupations

Adults aged 15+, 1901 and 1911 combined.

Farmer2,965
Farmer's son1,398
Farmer's daughter768
General labourer373
Farm servant355
Agricultural labourer343
Labourer302
Farm labourer276
House keeper227
Domestic servant199

Born outside Ireland

2.0% of Duffys in 1911 gave a birthplace outside Ireland.

England144
Scotland59
United States31
India5
Canada1
Wales1

Median age: 24 in 1901, 26 in 1911.

Given names

First names among the Duffys

Men and boys

  1. Patrick2,294
  2. John2,290
  3. James1,842
  4. Thomas1,349
  5. Michael1,259
  6. Peter568
  7. William525
  8. Edward476
  9. Francis435
  10. Joseph403

Women and girls

  1. Mary2,919
  2. Bridget1,732
  3. Catherine887
  4. Annie771
  5. Margaret744
  6. Ellen675
  7. Kate632
  8. Anne618
  9. Maggie490
  10. Elizabeth392

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

Spellings

Spellings

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

Spelling190119111926Records
Duffy11,88511,68910,038Search
Duffey726448147Search
O'Duffy152373Search

Related forms

  • O'Duffy — The form keeping the O prefix; Eoin O'Duffy, born Owen Duffy, adopted it.[1][12]
  • Duffey, Duffee — Spelling variants listed by Wikipedia.[7]
  • Duhig, Duhy — Munster forms of Ó Dubhthaigh.[1]
  • Dowey, Dooey, Doey — Ulster forms of the same name.[1]
  • Black — An occasional translation of the name, from dubh, 'black'.[1]

Diaspora

The Duffys abroad

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

SpellingPeopleUS rank
Duffy38,835892nd
Duffey6,2515562nd

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

Heraldry

Is there a Duffy coat of arms?

There is no single Duffy crest. Burke's General Armory records arms for O'Duffy of Ballyduffy, Co. Monaghan: a gold lion rampant on green. He also lists a separate Duffy coat, black with three red crescents on an ermine pale and an angel as crest, without naming the family it belonged to. Each coat belonged to a particular line, not to everyone named Duffy.[10]

Websites selling a single “Duffy 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 Duffy

  • Muireadhach Ua Dubhthaigh (died 1150)
    Archbishop of Connacht whose name is inscribed on the Cross of Cong.
  • Cadla Ua Dubthaig (archbishop 1161–1201)
    Second archbishop of Tuam, from the Lissonuffy church family.
  • Charles Gavan Duffy (1816–1903)
    Young Irelander and editor of The Nation who later entered politics in Victoria, Australia.
  • Hugh Duffy (1866–1954)
    American baseball outfielder and manager of the 1890s and 1900s.
  • Francis P. Duffy (1871–1932)
    Priest and chaplain of New York's 'Fighting 69th' regiment.
  • George Gavan Duffy (1882–1951)
    Barrister and TD, Minister for Foreign Affairs in 1922 and later President of the High Court.
  • Louise Gavan Duffy (1884–1969)
    Educator and Gaelic revivalist who founded the first Gaelscoil and was in the GPO in 1916.
  • James Duffy (1889–1969)
    Donegal-born soldier awarded the Victoria Cross in the First World War.
  • Eoin O'Duffy (1890–1944)
    Monaghan IRA leader, pro-Treaty army chief of staff, Garda chief and later fascist activist.
  • Eimar O'Duffy (1893–1935)
    Irish writer, involved in the nationalist movement until the 1916 Rising.
  • Eamon Duffy (born 1947)
    Irish historian of Christianity, emeritus professor at Cambridge.
  • Patrick Duffy (born 1949)
    American actor known as Bobby Ewing in the television series Dallas.

Questions

Questions about the Duffy name

Is Duffy an Irish surname?

Yes. Duffy is the English form of the Gaelic Ó Dubhthaigh, 'descendant of Dubhthach'. Woulfe found it all over Ireland and believed several unrelated families bore it, the most notable being a Connacht church family, a Monaghan sept and a Munster family. An unrelated Mayo name, Ó Doithe, was also turned into Duffy.[1][2]

What is Duffy in Irish?

Ó Dubhthaigh, now often spelt Ó Dufaigh; a woman's form is Ní Dhufaigh, as in the Irish name of the educator Louise Gavan Duffy. In Mayo some Duffys were originally Ó Doithe, a separate surname. Charles Gavan Duffy, the Young Ireland leader, was born Cathal Gabhánach Ó Dubhthaigh.[1][4][3][2][5]

What does Duffy mean?

It means 'descendant of Dubhthach', and Dubhthach is an old Irish personal name meaning black or dark, from dubh. Woulfe notes that the surname was occasionally translated into English as Black. In English the name was written in many ways, among them Duffy, O'Duffy, Duhig and Dowey.[1][7]

Are Duffy and O'Duffy the same name?

Yes. O'Duffy keeps the O of Ó Dubhthaigh, which most families dropped when the name was anglicised. Some later restored it: Eoin O'Duffy was born Owen Duffy. Duffey, Duhig and Dowey are further regional spellings of the same Irish name.[1][12][7]

Where does the Duffy name come from?

There is no single homeland. A famous church family came from Lissonuffy in north-east Roscommon, another family of note lived in Co. Monaghan around Clontibret, and Woulfe found the name common in Donegal and in Munster, where it was spelt Duhig. Mayo Duffys may instead descend from the Ó Doithe of Addergoole.[8][3][1][10][2]

Is there a Duffy family crest or coat of arms?

Not one for every Duffy. Burke records arms for the O'Duffys of Ballyduffy in Co. Monaghan, a gold lion rampant on green, and a separate Duffy coat with three crescents on an ermine pale. Arms belonged to particular families, so neither applies to all bearers of the name.[10]

Where in Ireland is the Duffy surname most common?

In the 1911 census the largest numbers of Duffys lived in Mayo (1,937), Donegal (1,570), Monaghan (1,503). Relative to population, the name was most concentrated in Monaghan (210 per 10,000), Mayo (101 per 10,000), Louth (98 per 10,000).

How common was the Duffy surname in Ireland?

12,160 people were recorded as Duffy or Duffey or O'Duffy in the 1911 census of Ireland, making it the 41st most common surname. That is roughly 0.3% of the population, or 1 person in 361.

Looking for a Duffy ancestor?

Search every Duffy 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 Dubhthaigh, in Irish Names and Surnames (1923)
  2. Patrick Woulfe, Ó Doithe, in Irish Names and Surnames (1923)
  3. Placenames Database of Ireland (logainm.ie), Lios Ó nDufaigh / Lissonuffy
  4. Wikipedia, Louise Gavan Duffy (2026)
  5. Wikipedia, Charles Gavan Duffy (2026)
  6. Patrick Woulfe, Ó Dúithche, in Irish Names and Surnames (1923)
  7. Wikipedia, Duffy (surname) (2026)
  8. Wikipedia, Muireadhach Ua Dubhthaigh (2026)
  9. Wikipedia, Cadla Ua Dubthaig (2026)
  10. Sir Bernard Burke, The General Armory of England, Scotland, Ireland, and Wales (1884). Entries 'O'Duffy' and 'Duffy'.
  11. Wikipedia, Cross of Cong (2026)
  12. Wikipedia, Eoin O'Duffy (2026)
  13. 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.
  14. Irish forms cross-checked against Gaois surname data (Fiontar & Scoil na Gaeilge, DCU).

How we compile these figures: methodology.