Show ContentsMacDermot History, Family Crest & Coats of Arms

Today's Irish surnames are underpinned by a multitude of rich histories. The name MacDermot comes from the Irish Gaelic Mac Diarmada, which means "son of Diarmuid," or, son of Dermot and belongs to the venerable Irish tradition of patronymic naming. However another source claims the name came from the Irish diarmaid, which meant "the god of arms." 1

Early Origins of the MacDermot family

The surname MacDermot was first found in County Roscommon (Irish: Ros Comáin) located in central Ireland in the province of Connacht, where the family is believed to have been descended from the Heremon dynasty of Irish Kings and were known as the Princes of Moylurg, or the Kings of Connacht, known as the Clann Mulroona. Specifically they were descended from Teige, a King of Connacht and his son, Murtogh, Prince of Moylurg. Their ancient territories were in the counties of Roscommon and Galway. They were divided into three septs. One of the septs embraced English rule early and relatively painlessly, the other two suffered at the hands of Strongbow's invasion in the 12th century. Of the other two septs, the more prominent is based in Coolavin, in Sligo. This sept was originally found at Moylurg and controlled a large part of Roscommon.

"The MacDermotts were ancient Princes of Moylurg, having their territories in the Barony of Boyle, County Koscommon, and parts of the Parishes of Islandeady, Turlough and Breaffy, in Counties Sligo and Mayo. Their chief fortress "was on an island in Lough Key, near Boyle," and they were hereditary Marshals of Connaught. At the present time Connaught is the province in which the MacDermotts are principally found, and half of the persons of the name in that province belong to County Roscommon. " 2

The head of this branch was one of the few leaders who is still credited as an authentic chieftain by the Genealogical Office of Ireland, conferring the rightful title The MacDermot. Moreover, the chief is also unofficially styled Prince of Coolavin. The third sept held a family seat at Kilronan in the north of Roscommon, and was referred to as MacDermot Roe, from the word ruadh, which means "red."

Early History of the MacDermot family

This web page shows only a small excerpt of our MacDermot research. Another 119 words (8 lines of text) covering the years 1172, 1251, 1320, 1592, 1641, 1707 and 1717 are included under the topic Early MacDermot History in all our PDF Extended History products and printed products wherever possible.

MacDermot Spelling Variations

Before widespread literacy came to Ireland, a name was often recorded under several different variations during the life of its bearer. Accordingly, numerous spelling variations were revealed in the search for the origin of the name MacDermot family name. Variations found include Dermott, Dermot, Dermitt, Dermit, McDermott, Dermutt, Dermut, MacDermott, McDermot, MacDermot, MacDermitt, McDermitt, MacDermit and many more.

Early Notables of the MacDermot family

Notable amongst the family name at this time was

  • Brian MacDermot (d. 1592) who held the famous manuscript "The Annals of Loch Cé"


United States MacDermot migration to the United States +

Thousands of Irish families left for North American shores in the 19th century. These people were searching for a life unencumbered with poverty, hunger, and racial discrimination. Many arrived to eventually find such conditions, but many others simply did not arrive: victims of the diseased, overcrowded ships in which they traveled to the New World. Those who lived to see North American shores were instrumental in the development of the growing nations of Canada and the United States. A thorough examination of passenger and immigration lists has disclosed evidence of many early immigrants of the name MacDermot:

MacDermot Settlers in United States in the 19th Century
  • Susana MacDermot, who landed in New York, NY in 1811 3
  • John MacDermot, who landed in New York, NY in 1816 3

Contemporary Notables of the name MacDermot (post 1700) +

  • Sir Dermot MacDermot,
  • Rory MacDermot (b. 1960), Prince of Coolavin, Chief of the Name


The MacDermot 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: Honor probataque virtus
Motto Translation: Honour and approved valour.


  1. O'Hart, John, Irish Pedigrees 5th Edition in 2 Volumes. Baltimore: Genealogical Publishing Company, 1976. Print. (ISBN 0-8063-0737-4)
  2. 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
  3. Filby, P. William, Meyer, Mary K., Passenger and immigration lists index : a guide to published arrival records of about 500,000 passengers who came to the United States and Canada in the seventeenth, eighteenth, and nineteenth centuries. 1982-1985 Cumulated Supplements in Four Volumes Detroit, Mich. : Gale Research Co., 1985, Print (ISBN 0-8103-1795-8)


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