Founded by Cistercian monks in 1148 and inhabited for nearly four centuries, this 56m-long, now-ruined abbey incorporates both Cistercian and Irish Romanesque architecture, with animal and human motifs inscribed on the stones. In the nave, its six surviving Gothic arches are supported by alternate square and round pillars; also still intact is the abbey's tower.
It's 12km southeast of Ballitore on the River Slaney's eastern bank; there are superb views from the western bank, where you'll find picnic tables.