Llandefalle sits just outside the Brecon Beacons National Park in Powys, South Wales. The village is 6 miles north of Brecon and 3 miles west of Talgarth. The Triffrwd river passes to the east of the village before its confluence with the rivers Dulas and Llynfi at Pont Trephilip, 3km south east of Llandefalle.

Originally dedicated to St Maelog, the church in Llandefalle is now dedicated to St Mathew. The present building probably originated in the late 13th Century or early 14th Century, but much of it is 15th Century. Importantly there appears to have been little if any Victorian restoration.

It contains a fine rood screen (dating from about 1500), a 13th Century font and fragmentary wall paintings, as well as a good range of 18th Century wall monuments. Parts of the present church are believed to date from c.1300, and it is possible that the lower part of the tower could be this early, while some of the masonry in the south aisle appears to conform with the early fabric but could be re-used. The rest is Perpendicular or later: most of the windows are of the 14th/15thC, contemporary with the arcade between the nave and aisle, and the porch has a possibly 16thC doorway.