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

The many Irish surnames in use today have long rich histories behind them. The name O'Mahoney originally appeared in Gaelic as Ó Mathghamhna, which is derived from the word mathghamhan, which means bear. 1 The modern Gaelic spelling is Ó Mahúna.

"Hugh Gharbh (or Hugh the Terrible), a younger brother of Laeghaire who is No. 93 on the 'O'Donaghue' (of Lough Lein) pedigree, was the ancestor of O'Mathamhna; anglicized O'Mahony and Mahony." 2

Early Origins of the O'Mahoney family

The surname O'Mahoney was first found in County Cork (Irish: Corcaigh) the ancient Kingdom of Deis Muin (Desmond), located on the southwest coast of Ireland in the province of Munster, where they held a family seat from ancient times.

"The O'Mahonys were anciently located in Cork and Kerry, where they were powerful Chiefs and sometimes styled Princes. They had several castles along the sea-coast. In County Cork an O'Mahony was Lord of Ivaugh, in the Barony of West Carbery, and an O'Mahony was Chief in Kinalea Barony. In County Kerry there was a Chief of the name in the Barony of Iveragh, and there were O'Mahonys in the Barony of Clanmaurice. The majority of persons of the name of Mahony or O'Mahony are still found in these two counties." 3

The Book of Munster clearly states: "The O'Mahony family were 'undisputed kings of Raithlean, and had a right to be kings of Cashel whenever that kingdom happened to be vacant; and from whom the Kings of Cashel had no right to demand anything except a bowing of the head.' " 2

Early History of the O'Mahoney family

This web page shows only a small excerpt of our O'Mahoney research. Another 179 words (13 lines of text) covering the years 1014, 1639, 1679 and 1987 are included under the topic Early O'Mahoney History in all our PDF Extended History products and printed products wherever possible.

O'Mahoney Spelling Variations

Many variations of the name O'Mahoney were found in archives from the Middle Ages. Names during the Middle Ages were typically recorded as they sounded and in many cases, one's surname spelling changed with each record.The spelling and language in which the people's names were recorded was often up to the individual scribe. Variations of the name O'Mahoney found include Mahoney, O'Mahoney, O'Mahony, Mahony and others.

Early Notables of the O'Mahoney family

Another 47 words (3 lines of text) are included under the topic Early O'Mahoney Notables in all our PDF Extended History products and printed products wherever possible.

Migration of the O'Mahoney family

Irish families fled the English-colonized Ireland in record numbers during the 19th century for North America. Many of those destitute families died from disease during, and even shortly after, the long journey. Although those that immigrated before the Great Potato Famine of the 1840s often were granted a tract of land, those that arrived later were generally accommodated in urban centers or in work camps. Those in the urban centers would labor in the manufacturing sector, whereas those in work camps would to build critical infrastructures such as bridges, canals, roads, and railways. Regardless of when these Irish immigrants came to North America, they were critical for the rapid development of the young nations of the United States and Canada. Early immigration and passenger lists have recorded many early immigrants bearing the name of O'Mahoney: Cornelius, Daniel, Denis, James, Jeremiah, John, Mary, Michael, Patrick, Peggy, Thomas, Timothy and William Mahoney, who all arrived in Philadelphia, Pennsylvania between 1840 and 1860.


RMS Lusitania
  • Mr. Thomas O'Mahoney, English Able-Bodied Seaman from England, who worked aboard the RMS Lusitania (1915) and survived the sinking 4


  1. MacLysaght, Edward, The Surnames of Ireland. Ireland: Irish Academic Press, sixth edition, 1985. Print. (ISBN 0-7165-2366-3)
  2. O'Hart, John, Irish Pedigrees 5th Edition in 2 Volumes. Baltimore: Genealogical Publishing Company, 1976. Print. (ISBN 0-8063-0737-4)
  3. Matheson, Robert E., Special Report on Surnames in Ireland with Notes as to Numeric Strength, Derivation, Ethnology, and Distribution. Dublin: Alexander Thom & Co., 1894. Print
  4. Lusitania Passenger List - The Lusitania Resource. (Retrieved 2014, March 7) . Retrieved from http://www.rmslusitania.info/lusitania-passenger-list/


Houseofnames.com on Facebook