The Irish surname Mahon is an anglicized form of Gaelic Mac Mathghamhna, a patronymic from the byname Mathghamhain meaning “good calf.” This was the name of two (unrelated) chieftain families in counties Clare and Monaghan. The most outstanding MacMahon was Edmond Patrice, Compte de MacMahon (1808 - 1893), Marshal of France, and President of the Third Republic for six years. The family Coat of Arms is a silver shield with three red lions passant reguardant in pale, armed and langued azure.