Irish Family Article
"Irish Families, Their Names, Arms & Origins" by Edward MacLysaght

Though MacQuillan is not a name of Gaelic origin it came into existence in Ireland and is not found elsewhere except among emigrants from Ireland, The MacQuillans are of Norman-Welsh descent; they settled soon after the invasion in the territory called the Route (Co. Antrim), and were known as Lords of the Route with their chief residence at the Castle of Dunluce until, following their major defeat at the battle of Ora in 1563 and again in 1580 by Sorley Boy MacDonnell, they were finally dispersed by the MacDonnells. In 1315 the MacQuillan chief of the day joined Edward Bruce. By the time they had become indistinguishable from any native Gaelic sept in the words of a contemporary "they were as Irish as the worst". They were described as Princes of Dalriada and ranked, at any rate in the fourteenth century, as hereditary High Constables of Ulster. Their predominant position was consolidated by Sincin Mor MacQuillan, who ruled as Chief from 1390 to 1449. As such they are prominent in the warlike activities of the O'Neills, O'Donnells and O'Cahanes in that province up to the date of the battle of Ora, mentioned above. Rory Og MacQuillan, then Chief of the Name, in 1541 declared that no captain of his race ever died in his bed. The last of the family of note in Ireland were Edward MacQuillan (1503-1605), whose remaining estate was confiscated in the plantation of Ulster, and Rory Og MacQuillan (d. 1634), to whom some of the estate was regranted. He was the last to be known as the "Lord of the Route". Subsequently, members of the sept are chiefly met with in France and Spain, in the Irish Brigades. One, Capt. Rory MacQuillan, was an officer in O'Neill's infantry in King James II's army in Ireland. Father Peter MacQuillan (c. 1650-1719) from Co. Derry became a leading Dominican in France, and later prior at Louvain, Many of the rank and file of the sept remained in Ulster as is evidenced by the prevalence of the name in Counties Antrim, Armagh, etc., in the Inquisitions, Hearth Money Rolls, 1659 census, etc., as well as modern birth indices, voters' lists and so forth. John. Hugh MacQuillan (1826-1879) a Quaker, was a pioneer of modern dentistry in America.

There is some doubt as to the derivation of the name. It is usually given as either son of Hugelin (deminutive of Hugh), or son of Hudelin (deminutive of Hud), the Irish forms being MacUighilin and MacUidhilin. MacFirbis describes the sept as Clan Uighilin. Some authorities, however, make the name a gaelicized version of son of Llewellyn, but Prof. Curtis, in a critical examination of the subject, rejects this and is convinced that the eponymous ancestor was Hugelin de Mandeville.