Llanrhaeadr-ym-Mochnant is a village in Powys, Wales, lying on the River Rhaeadr by the Berwyn Mountains.

The village is best known as the former parish of William Morgan, who first translated the Bible into Welsh. Attractions near the village include Wales' highest waterfall, the Pistyll Rhaeadr, known for its natural arch and its chaffinches. The village is also home to a shop selling tandem bikes.