O'Mahony History, Family Crest & Coats of Arms
The many Irish surnames in use today have long rich histories behind them. The name O'Mahony originally appeared in Gaelic as O Mathghamhna, which is derived from the word mathghamhan, which means bear. The modern Gaelic spelling is O 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." 
Early Origins of the O'Mahony family
The surname O'Mahony 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." 
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.' " 
Early History of the O'Mahony family
This web page shows only a small excerpt of our O'Mahony research. Another 179 words (13 lines of text) covering the years 1014, 1639, 1679 and 1987 are included under the topic Early O'Mahony History in all our PDF Extended History products and printed products wherever possible.
O'Mahony Spelling Variations
One must realize that attempting to record a Gaelic name in English was a daunting task. Even today the translation is a difficult one. Accordingly, spelling variations were the norm. Variations found include Mahoney, O'Mahoney, O'Mahony, Mahony and others.
Early Notables of the O'Mahony family (pre 1700)
Another 47 words (3 lines of text) are included under the topic Early O'Mahony Notables in all our PDF Extended History products and printed products wherever possible.
A great wave of Irish migration occurred during the 19th century as a direct result of English colonial rule and tight-fisted absentee landlords. Many of these Irish immigrants boarded passenger ships bound for North America. Those who migrated early enough were given land in either British North America or the United States; those who came in the late 19th century were typically employed in industrial centers as laborers. At whatever age they undertook the dangerous passage to North America, those Irish immigrants were essential to the speedy development of the two infant nations to which they arrived, whether they broke and settled land, helped build canals, bridges, and railroads, or produced products for consumer consumption. An examination of immigration and passenger lists has uncovered a large number of immigrants bearing the name O'Mahony or one of its variants:
O'Mahony Settlers in United States in the 20th Century