O'Fahey () is an anglicised form of Ó Fathaigh. The patronym means "descendant of Fathach", whose name means "base" or "foundation". Cormac Ó Fathaigh is the first recorded bearer with the surname and is the purported ancestor of any Ó Fathaigh descendants. The surname largely became Fahey, with many variations.
Notable descendants Pádraig Ó Fathaigh (1879–1976), Irish Republican Army intelligence officer
See also Anglicised versions of the surname: Fahey Fahie Fahy (surname) Fay (surname)
References