Coverage stretches from Mynydd Trawsnant and Cefn Coch eastward to Gwenddwr and Altmawr, and from Newbridge on Wye southward to Llandulas. The only towns are the small spa towns of Builth Wells and Llanwrtyd Wells; a third spa, Llangammarch Wells, was only regarded as a village by the OS.

Coverage stretches from Mynydd Trawsnant and Cefn Coch eastward to Gwenddwr and Altmawr, and from Newbridge on Wye southward to Llandulas. The only towns are the small spa towns of Builth Wells and Llanwrtyd Wells; a third spa, Llangammarch Wells, was only regarded as a village by the OS.