Llanwrtyd Wells is a market town and community in Powys, Wales, in the historic county of Brecknockshire on the Afon Irfon. The town is on the A483 between Llandovery and Builth Wells and is located near the pass between the Tywi and Irfon valleys. The community also includes the smaller settlements of Llanwrtyd and Abergwesyn, the valley of the Afon Irfon, and a large part of the "Desert of Wales".