The Irish surname McMurphy, also found in Scotland, is of patronymic origin deriving from the Gaelic name O'Murchu meaning "descendant of the sea-warrior." The McMurphy family are first found in County Wexford where they held an ancestral seat from early times. Today it's more common variant Murphy is the most common surname in Ireland with many bearers hailing from County Cork. McMurphy is the 24,827th most common name in the United states with over 900 bearers living there.