Show ContentsO'Brien History, Family Crest & Coats of Arms

Etymology of O'Brien

What does the name O'Brien mean?

The old Gaelic name used by the O'Brien family in Ireland was Ó Briain, which means descendant of Brian.

Early Origins of the O'Brien family

The surname O'Brien was first found in Thomond, a territory comprised of most of County Clare with adjacent parts of counties Limerick and Tipperary. Prior to the 10th century, the sept was a Dalcassian Clan known as the Ui Toirdealbhaigh and achieved prominence with the rise of their eponymous ancestor, Brian Boru (941-1014), to the High Kingship of Ireland. Brian Boru, by far the most outstanding figure of this family, is widely acknowledged as the greatest of all the ancient Kings of Ireland and is best remembered for driving the Norsemen out of Ireland at the Battle of Clontarf in 1014.

Early History of the O'Brien family

This web page shows only a small excerpt of our O'Brien research. Another 187 words (13 lines of text) covering the years 1369, 1400, 1551, 1577, 1600, 1614, 1640, 1642, 1651, 1663, 1674, 1678, 1690, 1692, 1699, 1714, 1717 and 1771 are included under the topic Early O'Brien History in all our PDF Extended History products and printed products wherever possible.

O'Brien Spelling Variations

Irish names recorded during the Middle Ages are characterized by many spelling variations. This preponderance of variations for common names can be explained by the fact that the scribes and church officials that kept records during that period individually decided how to capture one's name. These recorders primarily based their decisions on how the name was pronounced or what it meant. Research into the name O'Brien revealed many variations, including O'Brien, OBrine, O'Brion, O'Bryan, O'Bryen, McBrien, McBrine, Brian, Briand, Briant, Brine, Brines, Briens and many more.

Early Notables of the O'Brien family

Notable amongst the family name at this time was

  • Brian Sreamhach MacMathghamhna O'Brien, king of the Irish region of Thomond (1369-1400)
  • Daniel O'Brien (1577-1663), member of the Supreme Council of Catholic Confederates
  • Daniel O'Brien (d. 1690), founder of the Irish Brigade known as Clare's Dragoons
  • Murrough McDermod O'Brien, 1st Earl of Inchiquin and 6th Baron Inchiquin (1614-1674)
  • Henry O'Brien, Lord Ibrackan or Lord O'Brien (c.1642-1678), an Irish nobleman and politician
  • William McMurrough O'Brien, 2nd Earl of Inchiquin (c.1640-1692), an Irish nobleman
  • Charles O'Brien, sixth Viscount (1699-1771), Marshal of France
  • the Most Rev. Terence Albert O'Brien (1600-1651), Dominican Bishop of Emly who was hanged after the Siege of Limerick

O'Brien World Ranking

In the United States, the name O'Brien is the 281st most popular surname with an estimated 96,993 people with that name. 1 However, in Canada, the name O'Brien is ranked the 259th most popular surname with an estimated 15,900 people with that name. 2 And in Australia, the name O'Brien is the 869th popular surname with an estimated 4,558 people with that name. 3 New Zealand ranks O'Brien as 176th with 3,074 people. 4 The United Kingdom ranks O'Brien as 194th with 29,099 people. 5


O'Brien migration to the United States +

Under the rule of England, land ownership in Ireland changed dramatically, and many native Irish families found themselves renting out land to farm from absentee owners. This was one of the prime reasons that immigration to North America began in the late 18th century: Irish farmers dreamed of owning their own parcel of land to work for themselves. At this point, the immigrants were at least of modest means for the passage across the Atlantic was often quite dear. In the 1840s the Great Potato Famine created an exodus of people of quite different means. These people were most often destitute: they either sold anything they had to gain a passage or they were sponsored by philanthropic societies. Many of these immigrants were sick from disease and starvation: as a result many did not survive the long transatlantic journey. Although those settlers that did survive were often despised and discriminated against by people already established in these nations, they were critical to rapid development of the powerful industrial nations of the United States and the country that would later become known as Canada. An examination of immigration and passenger lists shows many persons bearing the name of O'Brien or one of its variants:

O'Brien Settlers in United States in the 19th Century
  • Andrew, Anne, Bridge, Catherine, Charles, Cornelius, David, Daniel, Denis, Edward, Frank, George, Henry, Hugh, James, John, Martin, Mary, Michael, Patrick, Peter, Thomas, and William O'Brien all, who arrived in Philadelphia between 1840 and 1870

O'Brien migration to Canada +

Some of the first settlers of this family name were:

O'Brien Settlers in Canada in the 19th Century
  • Henry O'Brien, aged 7, who arrived in Saint John, New Brunswick in 1833 aboard the brig "Dorcas Savage" from Belfast, Ireland
  • Peter O'Brien, aged 25, a labourer, who arrived in Saint John, New Brunswick in 1833 aboard the brig "Dorcas Savage" from Belfast, Ireland
  • Ann O'Brien, aged 20, who arrived in Saint John, New Brunswick in 1833 aboard the brig "Dorcas Savage" from Belfast, Ireland
  • Daniel O'Brien, aged 50, a tailor, who arrived in Saint John, New Brunswick in 1833 aboard the brig "Dorcas Savage" from Belfast, Ireland
  • Mary O'Brien, aged 5, who arrived in Saint John, New Brunswick in 1833 aboard the brig "Dorcas Savage" from Belfast, Ireland
  • ... (More are available in all our PDF Extended History products and printed products wherever possible.)

O'Brien migration to Australia +

Emigration to Australia followed the First Fleets of convicts, tradespeople and early settlers. Early immigrants include:

O'Brien Settlers in Australia in the 18th Century
  • Miss Mary O'Brien, (Brien), (b. 1768), aged 24, English convict who was convicted in Devon, England for 7 years, transported aboard the "Bellona" in July 1792, arriving in New South Wales, Australia, she died in 1853 6
O'Brien Settlers in Australia in the 19th Century
  • Mr. Cornelius O'Brien, Irish convict who was convicted in Tipperary, Ireland for life, transported aboard the "Atlas" on 29th November 1801, arriving in New South Wales, Australia 7
  • Mr. Denis O'Brien, Irish convict who was convicted in Wexford, Ireland for life, transported aboard the "Atlas" on 29th November 1801, arriving in New South Wales, Australia 7
  • Mr. James O'Brien, Irish convict who was convicted in Dundalk, Ireland for life, transported aboard the "Atlas" on 29th November 1801, arriving in New South Wales, Australia 7
  • Mr. John O'Brien, Irish convict who was convicted in Wexford, Ireland for life, transported aboard the "Atlas" on 29th November 1801, arriving in New South Wales, Australia 7
  • Mr. Maurice O'Brien, Irish convict who was convicted in Wexford, Ireland for life, transported aboard the "Atlas" on 29th November 1801, arriving in New South Wales, Australia 7
  • ... (More are available in all our PDF Extended History products and printed products wherever possible.)

O'Brien migration to New Zealand +

Emigration to New Zealand followed in the footsteps of the European explorers, such as Captain Cook (1769-70): first came sealers, whalers, missionaries, and traders. By 1838, the British New Zealand Company had begun buying land from the Maori tribes, and selling it to settlers, and, after the Treaty of Waitangi in 1840, many British families set out on the arduous six month journey from Britain to Aotearoa to start a new life. Early immigrants include:

O'Brien Settlers in New Zealand in the 19th Century
  • John O'Brien, aged 22, who arrived in Port Nicholson aboard the ship "Oriental" in 1840
  • Ellen O'Brien, aged 25, who arrived in Port Nicholson aboard the ship "Oriental" in 1840
  • Mr. John O'Brien, (b. 1817), aged 22, British settler travelling from London aboard the ship "Oriental" arriving in Port Nicholson, Wellington, New Zealand on 31st January 1840 8
  • Mrs. O'Brien, (b. 1814), aged 25, British settler travelling from London aboard the ship "Oriental" arriving in Port Nicholson, Wellington, New Zealand on 31st January 1840 8
  • Mr. O'Brien, Australian settler travelling from Sydney aboard the ship "Earl of Lonsdale" arriving in Bay of Islands, North Island, New Zealand on 11th April 1841 9
  • ... (More are available in all our PDF Extended History products and printed products wherever possible.)

Contemporary Notables of the name O'Brien (post 1700) +

  • Denis O'Brien (1941-2021), American attorney, and former business manager of George Harrison of the Beatles
  • Richard "Rich" O'Brien (1956-2017), American television director known for his work at Fox News
  • Glenn O'Brien (1947-2017), American writer, journalist and editor, known for his work with Rolling Stone and Interview
  • Walter Howard "Hod" O'Brien (1936-2016), American jazz pianist
  • Dan O'Brien Jr., American former general manager of Major League Baseball's Cincinnati Reds (2003-2006)
  • Dan O'Brien Sr. (1930-2017), American front office executive in Major League and minor league baseball, father of Dan O'Brien Jr
  • Donald Eugene O'Brien (1923-2015), United States district judge
  • Edward Joseph O'Brien (1930-2014), American Major League Baseball shortstop, outfielder and pitcher
  • Conan Christopher O'Brien (b. 1963), American television host, comedian, writer, producer and performer
  • Pat O'Brien (1899-1983), American film actor
  • ... (Another 36 notables are available in all our PDF Extended History products and printed products wherever possible.)

Halifax Explosion
  • Mrs. Maggie  O'Brien (1855-1917), Canadian resident from Halifax, Nova Scotia, Canada who died in the Halifax Explosion (1917) 10
  • Mr. Albert P.  O'Brien (1874-1917), Canadian resident from Halifax, Nova Scotia, Canada who died in the Halifax Explosion (1917) 10
  • Mr. Walter J.  O'Brien (1888-1917), Canadian resident from Halifax, Nova Scotia, Canada who died in the Halifax Explosion (1917) 10
HMAS Sydney II
HMS Royal Oak
  • Arthur Edward O'Brien (1901-1939), British Leading Seaman with the Royal Navy aboard the HMS Royal Oak (1939) when she was torpedoed by U-47 and sunk; he died in the sinking 12
RMS Titanic
  • Mr. Thomas O'Brien (d. 1912), aged 27, Irish Third Class passenger from Pallasgreen, Limerick who sailed aboard the RMS Titanic and died in the sinking 13
  • Mrs. Johanna "Hannah" O'Brien, (née Godfrey), aged 26, Irish Third Class passenger from Pallasgreen, Limerick who sailed aboard the RMS Titanic and survived the sinking 13
  • Mr. Timothy O'Brien (d. 1912), aged 21, Irish Third Class passenger from Drimoleague, Cork who sailed aboard the RMS Titanic and died in the sinking 13
SS Caribou
  • Mr. Jack F. O'Brien, British passenger who was Royal Air Force from Amherst, Nova Scotia was travelling aboard the railway ferry "SS Caribou" when it was struck by a German submarine torpedo on 14th October 1942, the most significant sinking in Canadian waters at that time, he survived the sinking
USS Arizona
  • Mr. Joseph Bernard O'Brien, American Private First Class from Illinois, USA working aboard the ship "USS Arizona" when she sunk during the Japanese attack on Pearl Harbor on 7th December 1941, he died in the sinking 14
USS Indianapolis
  • Arthur Joseph O'Brien, American crew member on board the ship "USS Indianapolis" when she was on a top secret trip for the first nuclear weapon, she was sunk by Japanese Navy on 30th July 1945, he was one of the many who were killed in the sinking due to exposure, dehydration, saltwater poisoning and shark attacks 15
Victoria steamboat disaster


The O'Brien Motto +

The motto was originally a war cry or slogan. Mottoes first began to be shown with arms in the 14th and 15th centuries, but were not in general use until the 17th century. Thus the oldest coats of arms generally do not include a motto. Mottoes seldom form part of the grant of arms: Under most heraldic authorities, a motto is an optional component of the coat of arms, and can be added to or changed at will; many families have chosen not to display a motto.

Motto: Lamh laidir an Uachtar
Motto Translation: The strong hand from above.


  1. "What are the 5,000 Most Common Last Names in the U.S.?". NameCensus.com, https://namecensus.com/last-names/
  2. "Surnames Meanings, Origins & Distribution Maps - Forebears." Forebears, https://forebears.io/surnames
  3. "Most Common Last Names in Australia." Forebears, https://forebears.io/australia/surnames
  4. "Most Common Last Names in New Zealand." Forebears, https://forebears.io/new-zealand/surnames
  5. "UK surname ranking." UK Surname map, https://www.surnamemap.eu/unitedkingdom/surnames_ranking.php?p=10
  6. Convict Records Voyages to Australia (Retrieved 5th October 2020). Retrieved from https://convictrecords.com.au/ships/bellona
  7. Convict Records Voyages to Australia (Retrieved 14th July 2020). Retrieved from https://convictrecords.com.au/ships/atlas
  8. New Zealand Yesteryears Passenger Lists 1800 to 1900 (Retrieved 26th March 2019). Retrieved from http://www.yesteryears.co.nz/shipping/passlist.html
  9. New Zealand Yesteryears Passenger Lists 1800 to 1900 (Retrieved 17th October 2018). Retrieved from http://www.yesteryears.co.nz/shipping/passlist.html
  10. Halifax Explosion Book of Remembrance | Maritime Museum of the Atlantic. (Retrieved 2014, June 23) . Retrieved from https://maritimemuseum.novascotia.ca/what-see-do/halifax-explosion/halifax-explosion-book-remembrance
  11. HMAS Sydney II, Finding Sydney Foundation - Roll of Honour. (Retrieved 2014, April 24) . Retrieved from http://www.findingsydney.com/roll.asp
  12. Ships hit by U-boats crew list HMS Royal Oak (08) - (Retrieved 2018 February, 9th) - retrieved from https://uboat.net/allies/merchants/crews/ship68.html
  13. Titanic Passenger List - Titanic Facts. (Retrieved 2016, July 13) . Retrieved from http://www.titanicfacts.net/titanic-passenger-list.html
  14. Pearl Harbour: USS Arizona Casualties List Pearl Harbour December 7, 1941. (Retrieved 2018, July 31st). Retrieved from http://pearl-harbor.com/arizona/casualtylist.html
  15. Final Crew List, retrieved 2021, October 30th Retrieved from https://www.ussindianapolis.com/final-crew


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