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

There are multitude of rich histories underlying the many Irish surnames in use today. The name O'Mulcahy originally appeared in Gaelic as Ó Maolchathaigh, which means "a descendant of a devotee of St. Cathach." The surname is not, as is often believed, derived from "cathach," meaning "warlike."

Early Origins of the O'Mulcahy family

The surname O'Mulcahy was first found in County Tipperary (Irish: Thiobraid Árann), established in the 13th century in South-central Ireland, in the province of Munster. 1 They claim descendancy from the Moores, hence the same shield. "John, a younger brother or Roger Caoch who is No. 114 on the 'Moore' pedigree, was the ancestor of Mulcahy." The author continues with a footnote, "From a similarity in the pronunciation of the names, some were of opinion the Maolcaich, who is mentioned in the Stowe Missal, might have been the ancestor of the family. " 2 From these early beginnings, two additional branches were established in Ardpaddeen and in Kilkenny. Of this latter branch, "the ancient fort or rath in the parish of Castleconor, County Sligo known as Rath Maoilcatha, has suggested the idea that this family may have derived their name from the Maolcatha after whom the rath is called; and therefore that they are descended from the royal stock from which branched the O'Connors, Kings of Connaught." 2

Early History of the O'Mulcahy family

This web page shows only a small excerpt of our O'Mulcahy research. Another 102 words (7 lines of text) are included under the topic Early O'Mulcahy History in all our PDF Extended History products and printed products wherever possible.

O'Mulcahy Spelling Variations

The scribes and church officials of the Middle Ages who recorded names in official documents spelled the names as they sounded. This led to the problem of one name being recorded under several different variations and thus resembling more than one person. Among the many spelling variations of the surname O'Mulcahy that are preserved in archival documents of this era include Mulcahey, O'Mulcahey, Mulcahy, O'Mulcahy, Mulcahee, Mulkey, McMulkey and many more.

Early Notables of the O'Mulcahy family

More information is included under the topic Early O'Mulcahy Notables in all our PDF Extended History products and printed products wherever possible.

Migration of the O'Mulcahy family

Ireland experienced a dramatic decrease in its population during the late 19th century. This was in a great measure, a response to England's imperialistic policies. Hunger and disease took the lives of many Irish people and many more chose to leave their homeland to escape such hunger and disease. North America with its promise of work, freedom, and land was an extremely popular destination for Irish families. For those families that survived the journey, all three of these things were were often attained through much hard work and perseverance. Research into early immigration and passenger lists revealed many immigrants bearing the name O'Mulcahy: John and Mary Mulcahy settled in Boston in 1849; along with Patrick; David, Denis, John, Thomas, Timothy, William Mulcahy all arrived in Pennsylvania between 1800 and 1860..



  1. MacLysaght, Edward, Irish Families Their Names, Arms and Origins 4th Edition. Dublin: Irish Academic, 1982. Print. (ISBN 0-7165-2364-7)
  2. O'Hart, John, Irish Pedigrees 5th Edition in 2 Volumes. Baltimore: Genealogical Publishing Company, 1976. Print. (ISBN 0-8063-0737-4)


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