In those days the McCormack was the name of a powerful Sept (Clan or Family) in the county of Longford,[citation needed] Cormac mac Airt, a semi-historical Irish high king who ruled from Tara ca.
Cormac, son of Cabhsan, was the first chieftain to be called Cormack, and, of course, MacCormack came later as a direct descendant, Mac or Mc signifying the 'son of'.
In 1576, 1598 and 1600, MacCormicks are recorded as leading gentry in County Cork[3] and one, of Muskerry, was influential enough to raise a large force to assist Desmond in the Elizabethan wars.
The Annals of the Four Masters record the deaths of several prominent MacCormicks of County Fermanagh; the last of these died in 1431.
[4] Scottish and Irish patronymic surnames frequently have the prefix Mac or Mc.