Saint Cellach of Glendalough

Saint Cellach or Ceallach was an early medieval saint associated with Glendalough in County Wicklow, Ireland.

Martyrology of Tallaght refers to him as a Saxon. He was a deacon, and lived to the southeast of Glendalough at a place called Disert-Cellaig which denotes a hermitage and implies that Cellach may have lived as a recluse. In the Irish life of Saint Kevin he is mentioned as having been ordered to go to Disert Cellaig as a penance 'for his vanity.' His feast day is 7 October.