St Sawyl's Church is situated within an oval churchyard, immediately south of the Afon Marlais and some 35m north of the Afon Melinddwr. Sources differ as to whether the chrch was a parish church during the medieval period. In a charter issued by Edward III it is referred to as the chapel, Pistyll Sawy. The church was referred to as a chapel in 1790, but was a parish church by 1833. A small cross-incised stone, within the external face of the nave's south wall, was uncovered during the 1868 restoration. A former school room (NPRN 418971) is situated adjacent to the south-west churchyard boundary. The school was superseded by the present village school around 1875.

The church is a Grade II listed building, constructed of mixed local rubble stone. It consists of three-bayed nave, two-bayed chancel, three-storeyed west tower and vestry (north of chancel west bay). The church's single aisle plan and squints (on either side of the chancel arch) are noted as unusual for north-eastern Carmarthenshire. The nave and chancel are thought to be fourteenth century in date. The tower was added around 1500. The square Old Red Sanstone font is medieval (but retooled) and was formerly free-standing. The church was restored in the 1860s, and a small vestry present in 1885 may have been added at this time. The church was again restored in 1887, to the designs of J. Middleton, Westminster and Cheltenham. A doorwat at the west end of the nave wall was blocked at this time. The church was refenestrated (apart from side windows of east bays of nave and chancel), reroofed, refloored, reseated and replastered. The vestry was also rebuilt to a larger plan. A tomb recess or Easter sepulchre was noted in 1913, underneath a window in the north wall. The opposite window retained shutter hinges and fastening at that time.

Sources include:
Cambria Archaeology, 2000, Carmarthenshire Churches, gazetteer, 48

N Vousden, RCAHMW, 21 May 2013