Saighir, is a monastic site in Clareen, County Offaly, founded by Ciarán of Saigir.

Ciarán of Saigir, also known as Ciarán mac Luaigne or Saint Kieran, was one of the Twelve Apostles of Ireland and is considered the first saint to have been born in Ireland, although the legend that he preceded Saint Patrick is questionable. Ciarán was bishop of Saighir (Seir-Kieran) and remains the patron saint of its successor, the diocese of Ossory.