Fincath mac Garrchu (or Findchad mac Garrchon) (died 485) was a
king of Leinster. He was a member of the
Dál Messin Corb dynasty's principal sub-sept, the
Uí Garrchon. He was the son of the founder of this sept Garrchú mac Fothaid.[1]
Not mentioned as king in the Book of Leinster, he is however given this title in the Annals of Innisfallen. He was defeated and killed in the first Battle of Grainaret in 485 by the
Uí Néill. The victor of this battle is variously given as
Coirpre mac Néill or
Muirchertach mac Ercae.[2] Coipre mac Neill was probably the victor and it may record the conquest of north Tethbae and that it was fought near
Granard (
County Longford)[3]