Holy Trinity church is situated on the north bank of the Afon Cothi, less than a kilometre north of Pont-ar-gothi. The church, a Grade II* listed building, is regarded as being without parallel in Wales with its exceptionally elaborate and well-preserved interior decorative scheme.

The church was built, in a simple Romanesque style with some Gothic detailing, in the period 1865-78 to designs of architect Benjamin Bucknall, on behalf of Henry James Bath of Allyferin (NPRN 191). It is constructed of local stone with Bath stone dressings and comprises four-bay nave with lower and narrower two-bay chancel and Gothic timber spirelet above, north-east vestry and west gable entrance. The design is influenced by Viollet-le-Duc in its styleless combination of forms: round arches, Gothic spirelet and modern bargeboards.

Inside, the nave has a boarded wagon roof and, the chancel has a keeled wagon roof, and at the west end of the nave is a glazed wooden porch screen. The interior walls and roofs are entirely covered with painted decoration, comprising a total of 31 individual wall paintings, sequenced chronologically from west to east. The nave has a moulded band beneath the roof, then a painted acanthus frieze, below which is a band of fictive blocks. Between the windows are biblical scenes within painted Gothic arches. The windows have painted reveals, some with painted memorial inscriptions, and beneath the sills is a further band of decoration. The west wall is decorated in similar fashion with passages from the Bible enclosed in painted arches. The chancel decoration is in similar style but more elaborate, with gilding to painted arches, and a painted band imitating wall hangings at dado level. The roof has richer painted decoration over the sanctuary (see notes page for details on these paintings). The stained glass is by Clayton and Bell and the spectacular painted interior decoration is by Arthur Stansell, of Taunton under Swansea-based architect, Benjamin Bucknall's direction. There is a hexagonal belfry and wooden spire.

Sources include:
Cadw, Listed Buildings Database
T.J. Hughes, 2006, Wales's Best One Hundred Churches.
T.Lloyd, J.Orbach & R.Scourfield, Buildings of Wales: Carmarthenshire and Ceredigion (2006), p.366.
Richard Suggett, Painted Temples: Wallpaintings and Rood-screens in Welsh Churches, 1200–1800, (RCAHMW 2021).

RCAHMW 2021