Cwmhir Abbey (Welsh: Abaty Cwm Hir), near Llandrindod Wells in Powys, is a Welsh Cistercian monastery founded in 1176 by Cadwallon ap Madog. A spurious tale was later recorded that the abbey was founded in 1143 by Meredudd ap Maelgwn at Ty-faenor, and then refounded at the present location near the village of Abbeycwmhir in 1176. There does appear to be a site movement from Ty-faenor, but Maredudd ap Maelgwn was prince of Maelienydd in 1215 under Prince Llywelyn ab Iorwerth of Gwynedd, who then controlled the district.