St Twrog's Church is situated within a roughly subcircular churchyard, bounded by a road on its west side. The church wasa parish church during the medieval period, belonging to the Deanery of Stradtowy. At that time it was a possession of the Bishop of St Davids, as a prebend of the collegiate church at Brecon. The patronage had not changed in 1833. Also in 1833, it was noted that there were the slight remains of a chapel of ease, St Bernard's, in the parish, but that the chapel had been in ruins for nearly two centuries. The churchyard walls, including lych gate and fold (NPRN 419160) constitute a Scheduled Ancient Monument.

There is no physical evidence of the pre-1860 church. It was noted as a small edifice, and is thought to have has a relatively short and wide nave, chancel and south transept.Three bells were noted in the sixteenth century. In 1731-1732 the windows were reglazed and the bell rehung.

The church was entiely rebuilt in 1860, to the designs of R. Kyrke Penson. The present church is a Grade II listed building, considered of interest as a Gothic Revival church with prominent spire and good interior detail. The church is constructed of Old Red Sandstone ashlar and rubble with yellow ashlar dressings (from 1860). It consists of three-bayed nave, three-bayed chancel, three-bayed north chapel (now vestry), three-bayed north aisle, south porch, three-storey tower, transeptal vestry (south of chancel), below-ground coalhouse (east of vestry) and boilerhouse (east of coalhouse). The north chapel (now vestry) was known as the Puxley Chapel in 1861. The tower was renovated in 1996.

Sources include:
Cadw, Listed Buildings Database
Cambria Archaeology, 2000, Carmarthenshire Churches, gazetteer, 48

N Vousden, RCAHMW, 1 July 2013