Dempsey Surname Meaning, History & Origin

Dempsey Surname Meaning

Dempsey is an anglicized version of O’Dempsey, the ancestor of O’Diomsaigh. This family name came from the Gaelic word diomusach, meaning “proud” or “haughty.” The O’Diomsaighs originated in the territory known as Clanmalier, on the borders of what are now the Laois and Offaly counties in Ireland.

Dempsey Surname Resources on The Internet

Dempsey Surname Ancestry

  • from Ireland (Laios and Offaly)
  • to England, America and Australia

Ireland.  The Annals of the Four Masters recorded in 1193 the death of Dermot O’Dempsey, son of Cubgogda. He was Chief of Clanmalier, for a long time Lord of Offaly, and the founder of the Cistercian abbey at Monasterevan in county Kildare. He also led the Leinster resistance against the Anglo-Norman invasion in the 1170’s under Strongbow and defeated him in battle.

The O’Dempsey territory, known as Clann Mhaoilughra, comprised a vast area on both sides of the Barrow river and included the baronies of Philipstown in Offaly, Portnahinch in Laios, and West Offaly in Kildare. Lea Castle in Portnahinch, often occupied by the O’Dempseys, lay in the center of these lands. Successive O’Dempsey clan chiefs held onto their territory.

In the 16th century, the O’Dempseys were on friendly terms with the English, fighting with them in their attacks on the Irish clans at Mullamast in 1577, and their estates escaped confiscation. Terence O’Dempsey was knighted in 1599 and created Viscount Clanmalier in 1631.

The O’Dempseys then switched sides. Three of their number were prominent members of the Confederation of Kilkenny during Cromwellian times. Loyalty to the Catholic King James II then resulted in the forfeiture of all their lands in 1691. O’Dempseys had been prominent in the Battle of the Boyne. Many O’Dempseys were evicted from their homes and driven into neighboring counties such as Tipperary.

As one English commentator noted:  “Viscount Clanmalier was head of this family at the Revolution of 1688. They are now obscure and sunk into poverty and degradation.”

This clan history has most recently been recorded in Patrick Goode’s 2008 book The O’Dempsey Chronicles.

The Dempsey name is still strong in Laois and Offaly, particularly in their own homeland, but it has also spread throughout Ireland. It is quite common in county Antrim in Ulster where it may be an Irish version of the Scottish name Dempster. There were a number of Presbyterian farming families called Dempsey in the parishes of north Antrim in the 19th century.

England. After the confiscation of the Clanmalier lands in 1691, Terence O’Dempsey left Ireland and settled in Cheshire. A descendant of this line was General Sir Miles Dempsey, a commander of the British Second Army during the D-Day landings in 1944.

James and Ann Dempsey were married in Liverpool in 1821 and James was a timber merchant.  “The anecdotal account was that the Dempsey family emanated from Ireland and that the daughters of James and Ann were known as ‘the Dempsey beauties.'”

These Dempseys were part of a close-knit coterie of Liverpool merchant families which often intermarried. Daughter Ann Dempsey married the shipowner Thomas Holderness, daughter Frances the merchant William Tarbet, daughter Louisa the Liverpool MP John Torr, and daughter Maria the banker John Smith.

Many Dempseys came from Ireland to industrial Lancashire in the second half of the 19th century, in search of jobs.

America. The earliest Dempsey arrival in America was probably William Dempsey who came to Philadelphia in 1726 as a young boy and made his home in Virginia. Barnet Dempsey from county Kildare came to Spartanburg, South Carolina sometime in the 1780’s. His son Levi moved onto Georgia.

Captain Michael Dempsey, who emigrated to America in the 1830’s, was from Lea parish in Laois and believed to be related to the Dempseys of Clanmalier. He enlisted in the US Army, fought in Florida in the Seminole Indian War, and ended up farming in Catahoula parish, Louisiana.

More Dempseys arrived later in the 19th century via ports in the northeast. Among them were:

  • Michael Dempsey and his sisters from Dublin onboard the Mount Washington to Boston in 1849. They settled in the Boston area.
  • and Lawrence Dempsey from Wexford onboard the Monongahela to Philadelphia in 1850. Lawrence later married and they moved to Lee county, Illinois to farm. A Dempsey still lives on part of their farm today.

John Dempsey arrived with his family from Tipperary in 1925. He rose through the political ranks to be Governor of Connecticut from 1961 to 1970.

There were two famous Jack Dempseys in America who were world boxing champions:

  • the first Jack Dempsey, known the Jack Dempsey the non pareil, came from Ireland but spent most of his boxing life in America. Sadly, he died young of TB.
  • the second, known as the Manassa Mauler, was born in Colorado from a family that had hailed originally from West Virginia. He lived on after retirement to run Jack Dempsey’s Restaurant in New York.

Australia. James Dempsey, a United Irishman, had been part of the Vinegar Hill rebellion in Wexford in 1798, resulting in his transportation to Australia. He was granted his freedom in 1809 and his home became a spiritual and communal center for the sizeable disenfranchised Irish Catholic population of Sydney. He devoted his time, money, and effort in later life to the building of the first Catholic chapel in Australia for this community.

Among the later free settlers to Australia were:

  • Thomas O’Dempsey and his family on the Ballarat from Wexford in 1828. They arrived in Melbourne.
  • Newly-weds James and Johanna Dempsey from Tipperary in 1855. They came to Queensland and were one of the early settlers in Upper Freestone.

Dempsey Surname Miscellany

The O’Dempseys of Clanmalier.  The following is the O’Dempsey line, from Dermod O’Dempsey’s father who died in 1162 through fourteen generations to the O’Dempseys in the 17th century.

Name Date of Death
Conbrogha McHugh O’Dempsey   1162
Dermod McConbrogha O’Dempsey   1193
Hugh McDermod O’Dempsey
Fionn McMalachy O’Dempsey   1306
Dermod McFionn O’Dempsey   1308
Fionn McDermod O’Dempsey
Malachy McFionn O’Dempsey   1329
Dermod McMalachy O’Dempsey   1383
Maolmorra McDermod O’Dempsey   1407
Cahir McMaolmorra O’Dempsey   1445
Dermod McCahir O’Dempsey
Hugh McDermod O’Dempsey   1563
Dermod McHugh O’Dempsey   1565
Terence McDermod O’Dempsey   1639

Terence O’Dempsey was made Viscount Clanmalier by James I of England in 1631.  His grandson Lewis the second Viscount (who died in 1683) and great grandson Maximilian the third Viscount (who died in 1714) took up against the English and their lands were forfeited in 1691.

The O’Dempseys and Lea Castle.  Lea Castle lies on the outskirts of what is now the town of Portarlington, on the banks of the Barrow river between Laois and Offaly.  The castle was originally built by the Normans in 1260, but it changed hands many times during its history.  It was taken by the O’Dempseys in 1284 then surrendered in 1329, burned by the O’Moores in 1346, captured by the O’Dempseys in 1422, and then taken by the Earl of Ormond in 1452.

In 1642 the castle was occupied by the Confederate Catholics, from which they were driven by Lord Lisle.  Eight years later the castle was taken by Cromwell’s forces and dismantled. The last person who took up his abode there was Charles O’Dempsey (Cahir na gCapall), the last descendant of the once powerful Chiefs of Clanmaliere.

Dempseys of Lea Parish in Laios County.  Griffith’s Valuation of Ireland was undertaken over the years 1848 to 1864.  It recorded the property owners in each county.  Those in Queen’s county (now Laois county) showed sixty three Dempseys.  Ten of them below were from Lea parish.

Name Parish Location
Andrew Dempsey Lea Kilbride
John Dempsey Lea Cooltedery
John Dempsey Lea Cooltedery (Bracklone St)
John Dempsey Lea Cooltedery (Main St)
John Dempsey Jr Lea Cooltedery (Main St)
Joseph Dempsey Lea Clonanny
Margaret Dempsey Lea Jamestown/Ballyteigeduff
Mary Dempsey Lea Cooltedery (Main St)
Michael Dempsey Lea Courtwood
Patrick Dempsey Lea Bolnagree

Reader Feedback – William Dempsey in Philadelphia in 1726.  In your Select Dempsey Surname Genealogy you say that Barnet Dempsey may have been the earliest Dempsey arrival in America during the 1780’s.

I have family written history that William Dempsey (my 5th great grandfather), age 4, arrived in Philadelphia in 1726 in the company of his uncle Mark.

His son, John William Dempsey (my 4th great grandfather), fought under Washington in the American Revolution and may have been at Valley Forge. John married Rachel Solomon (daughter of a Jewish sea merchant) in Philadelphia after the conclusion of the war and around 1790 made residence in Botetourt county, Virginia (now Mingo county, West Virginia).  His father William had lived at Fincastle in Botetourt county.

Mark Dempsey (

Reader Feedback – Arthur O’Dempsay from Dublin to America.  I am looking for the parents of Arthur David O’Dempsay.  Born in Dublin in 1812, he trained as a MD in Ireland, (his father was probably an MD) and was reported to be a seminary student, age 15/16, at maybe Clongowes Woods.

He landed in Vermont in 1829 with wife Mary Ann Smith and baby Jane born at sea when the father was 17 years old.  I wonder if a pregnancy had caused his marriage to Mary and their trip to America as a couple.  He died in Washington, Illinois in 1895.  His tombstone and land records spelt name with an “a” (Dempsay).

Kathy Olin (

James Dempsey and the Early Catholic Church in Australia.  In the Catholic archives in Adelaide were found some anonymous scribbled notes which read as follows:

“James Dempsey, a stone mason, sent out for the part he took in the rising of 1798 was a native of Wexford.  A man of genuine piety, he often wept in his captivity, for though his irreproachable character caused him to be allowed to execute his trade and exempted him from being assigned, he felt his deprivation of all religious aid as keenly as the Jews who ‘could not sing the songs of the Lord in a strange land, who wept when they remembered Zion.'”

He had been granted his pardon in 1809, the year the only Roman Catholic priest in the New South Wales colony had been expelled. An unconsumed Host was left behind by the priest and Dempsey kept this at his house on Kent Street and used it as a rallying point for the large Catholic population in Sydney.

When a priest finally arrived in 1820, Dempsey was still filled with zeal and went about the construction of the first Catholic chapel in Australia.  He started work on an undesirable piece of land on the outskirts of the town.  He was to sink his whole fortune into its building and it was to become his life’s work.  It pushed him into bankruptcy and he travelled the world to raise funds for it.  The chapel was finally completed some years before his death in 1838.

Jack Dempsey the Nonpareil.  Jack Dempsey was born in county Kildare in Ireland, but died of TB in America in 1895.  He was just thirty three.

He was a middleweight boxer who became champion of the world. Some people think that he was the greatest pound for pound boxer in history.   He was a two-handed fighter who could box or punch; his jab was quick and accurate; his right hand punch was stiff; he was game and cool under pressure; and he could fight whatever style was needed to win; in short, a crafty boxer-puncher who was an excellent ring general.

M.J. McMahon wrote a poem to his memory.  Part of the poem read as follows:

  • “Far out in the wilds of Oregon,
  • On a lonely mountainside,
  • Where Columbia’s mighty waters
  • Roll down to the ocean side;
  • Where the giant fir and cedar
  • Are imaged in the wave,
  • O’ergrown with firs and lichens,
  • I found Jack Dempsey’s grave.
  • O Fame, why sleeps thy favored son
  • In wilds, in woods, in weeds,
  • And shall he ever thus sleep on,
  • Interred his valiant deeds.
  • Tis strange New York should thus forget
  • Its ‘bravest of the brave’
  • And by the fields of Oregon,
  • Unmarked leave Dempsey’s grave.”

Jack Dempsey’s Restaurant.  Jack Dempsey’s was a New York restaurant located on Broadway between 49th and 50th streets in Manhattan.  Owned by world heavyweight boxing champion Jack Dempsey, it was considered by many as an American institution.  It originally opened for business in 1935 on Eighth Avenue and 50th Street, directly across from the old Madison Square Garden.  Most nights would find Dempsey’s famous proprietor on hand to greet guests, sign autographs, pose for pictures and hold court.

A poster in the restaurant showed Dempsey crouching and bobbing his way to a heavyweight victory over the giant Jess Willard to win the championship of the world on July 14, 1919.

Jack Dempsey’s restaurant appeared in the 1972 movie The Godfather.  Michael Corleone stood in front of Jack Dempsey’s while waiting to be picked up by Virgil Sollozzo and Capt. McCluskey for their infamous dinner meeting.   The restaurant closed two years later in 1974.

Dempsey Names

  • Dermot O’Dempsey, who died in 1193, was the first leader of the O’Dempsey clan. He led the Leinster resistance to the Anglo-Norman invasion under Strongbow.
  • James Dempsey built the first Roman Catholic chapel in Australia.
  • Jack Dempsey (born John Kelly) was an Irish-born boxer called the “nonpareil” because no one could beat him. He died in 1895 at the tender age of 33.
  • Jack Dempsey, known as the “Manassa Mauler,” was world heavyweight champion from 1919 to 1926.

Dempsey Numbers Today

  • 8,000 in the UK (most numerous in London)
  • 10,000 in America (most numerous in New York)
  • 16,000 elsewhere (most numerous in Ireland).

Dempsey and Like Surnames 

The Irish clan or sept names come through the mists of time until they were found in Irish records such as The Annals of the Four Masters.  The names were Gaelic and this Gaelic order was preserved until it was battered down by the English in the 1600’s.

Some made peace with the English.  “Wild geese” fled to fight abroad.  But most stayed and suffered, losing land and even the use of their language.  Irish names became anglicized, although sometimes in a mishmash of spellings.  Mass emigration happened after the potato famine of the 1840’s.

Some surnames – such as Kelly, Murphy and O’Connor – span all parts of Ireland.  But most will have a territorial focus in one of the four Irish provinces – Leinster, Munster, Ulster, and Connacht.

Leinster in SE Ireland covers the counties of Carlow, Dublin, Kilkenny, Offaly, Laois, Longford, Louth, Meath, West Meath, Wexford, and Wicklow.  Here are some of the Leinster surnames that you can check out.



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Written by Colin Shelley

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