Portumna Friary was originally a Cistercian chapel which was dedicated to St. Peter and Paul in the 13th century. The site later became abandoned and a local chieftain at the time handed it over to the Dominicans whom, with consent from the Cistercians, erected a friary and church on the site which were dedicated to the Blessed Virgin Mary. In 1426, a papal bull was granted, confirming their possessions, by Pope Martin V.
In 1689, the Irish Jacobite leader, Patrick Sarsfield was married to Honora de Burgo at the church. The remains today consist of a church with nave, chancel and transepts along with outlines of surrounding domestic buildings.