St Llwchaiarn's is a Georgian church built in brick 1815-16 on the site of an earlier stone church. The chancel was replaced in 1865 by R.J.Withers who provided Decorated windows. The church consists of nave with rusticated brick quoins under a gently-pitched slate roof, west tower-porch, narrower chancel with steeply-pitched roof - its gable contrasting with the pedimented east end of the nave - and gabled south vestry. The rectangular tower is of three stages with freestone obelisk finials on a corniced parapet, louvred round arched openings to the bellstage, stone sills, and round windows to the first stage, blocked to form sundial to the south. A stone panel dated 1815 is set over a round arched west door.
The most notable feature of the interior are portions of a fine screen of c.1500, originally from St Mary's Newtown, then moved to the new church of St David's in 1856 and then to Llanllwchaiarn in 2011. The parts, which had become dispersed following the screen's dismantling in 1875, are now assembled in the gallery.
Fittings include a reredos of 1902 which incorporates some carved panels from Welshpool church. Pews and pulpit ae by Withers. Glass includes works by O'connor (1864 & 1868), William Morris (1870) and C.A.Gibbs (1874).

Sources:
Extracts from Cadw Listing description.
R.Scourfield & R.Haslam, Buildings of Wales: Powys (2013), p.177-8.

RCAHMW, 27 July 2015