Origin of the MacMahon Clan Name


The name McMahon is an anglicised from of the Irish name Mac Mathghamhna which means “bear or good calf”. Later on the name became MacMathuna. The surname arose separately in two distinct areas, County Clare and County Monaghan. In the former, the Mac Mahon’s originated from the counties of Clare and Limerick in Munster and were part of the Dál gCais Tribe. They descend from Brian Boru through his grandson. Mahons son was the first the carry the name MacMahon, which means Son of Mahon.

McMahon Family Crest

Brian Boru’s brother also named Mahon, was murdered by the Norse together with the Eoganachta after he overthrew them from the Rock of Cashel. They became lords in the area of south-west Clare. The Mac Mahons motto is Sic Nos Sic Sacra Tuemur with means “thus We Defend Our Sacred Rights”.

Earliest settlers outside of Ireland include Morgan McMahon in 1746, who arrived in Philadelphia in Pennsylvania.

Additional names included McMahon, MacMohan, Mahon, Maghan, Mann, Maugha and many more.