Holy Trinity Abbey

Holy Trinity Abbey is a medieval monastery on Trinity Island in Lough Key, constructed from pale grey sandstone and limestone with a preserved west gable and pointed window. The building occupies the small island and displays typical features of medieval monastic architecture.

The monastery was founded in 1215 by Clarus Mag Máilin, archdeacon of Elphin, and received monks from Boyle Abbey in 1228. It gained abbey status in 1235, establishing itself as a monastic center.

The Annals of Lough Key, a significant medieval manuscript recording Irish events, was composed by monks living here between 1014 and 1590. This work shows how important the monastic community was for documenting regional history.

The archaeological site requires boat access to the island, as it covers about 0,9 hectares within Lough Key. Local operators offer guided tours to help visitors explore this remote location.

During an archaeological excavation in 1991, silver coins from the periods of Henry VIII and Elizabeth I were discovered on the monastery grounds. These coins suggest economic connections and trade with England.

Location: County Roscommon

GPS coordinates: 53.98922,-8.25451

Latest update: December 9, 2025 20:20