Kilmacduagh monastery, Abbey and national monument near Gort, Ireland

Kilmacduagh monastery stands in the village of Kilmacduagh, about 5 km from Gort in County Galway. Its ruined abbey church, the former cathedral, has a long low wall of grey and brown rough-cut stone with two small round-arched windows and a narrow slit, and a taller gabled section on the right with two tall narrow round-arched windows in dressed stone surrounds. A round tower leans over half a metre from the vertical roughly 15 m south-west of the cathedral.

Saint Colman, son of Duagh, founded the monastery in the early 7th century on land given by his cousin King Guaire Aidne mac Colmáin of Connacht. It became the seat of the Diocese of Kilmacduagh in the 12th century. After raids, William de Burgh ruined the early monastery in the early 13th century, and Owen O'Heyne founded the Augustinian abbey of St. Mary de Petra to replace it.

The name Kilmacduagh means "church of Duagh's son", referring to Saint Colman MacDuagh. The O'Heyne's Church, built in the first half of the 13th century, has a doorway above the chancel with carved stonework on columns decorated with flowers and animals. The O'Heyne clan claimed King Guaire Aidhne as an ancestor.

The ruins stand in an open field about 5 km from Gort, with the buildings dispersed around a graveyard; the round tower is roughly 15 m south-west of the cathedral and O'Heyne's Church about 180 m north-east. Paths are grass and uneven stone, so stout footwear and rain gear help. The tower's only doorway is some 7 m above ground and is not reached from the field.

The round tower here ranks among Ireland's tallest medieval stone structures, yet it leans noticeably due to foundation issues that developed over time. This visible tilt makes it one of the most recognizable features visitors encounter on the grounds.