St Margaret's Church is situated within a circular churchyard, bounded by the B4314 on its southern side. Historic (1889) Ordnance Survey mapping also depicts two routeways (now visible as tracks) converging from east and west shortly before they reach the northern churchyard boundary. At this point they branch again to follow east and west churchyard boundaries, before joining the B4314 either side of the churchyard. The churchyard overlies a Bronze Age site, and evidence of Bronze age cremations were discovered in 1856. A fifth-sixth century inscribed stone was found in the churchyard around 1880, and is now in the church. Its Latin inscription reads 'AVITORIA FILIA CVNIGNI', and it also has clear Ogham strokes, reading 'AVITTORIGES' along the top and 'INIGINACUNIGNI' along the bottom. A similar stone can be found in St Margaret Marlos Church, Llandawke (NPRN 103877). The oak lych gate (NPRN 418467) dates to 1930. The old rectory (now Gymmin House), erected in 1869-1870, is situated some some 30m south of the churchyard. A hall, depicted as Common Church Cottage on historic (1889 and 1906) Ordnance Survey mapping, is immediately adjacent to the south-east churchyard boundary (its curtillage dilineated by the angle between churchyard boundary and the east of the two routeways mentioned above).

The church is a grade I listed building, constructed of rubble stone, with grey limestone copings. It consists of four-bayed nave, three-bayed chancel and south porch. The western part of the nave is wider that the rest, and may date to the earlier twelfth century. The building was extended to the east in the (probably earlier) thirteenth century, when a chancel was added (on the site of the present chancel, which is a copy). The limestone font is medieval, although its basin and stem are both from different fonts. The nave vault dates from the fourteenth century, when the north wall was internally thickened to be flush with it, and the present nave south door was added. The church's internal flloor level was raised and the porch was also addded at this time. It partly covers a low pointed arch with stone voussoirs, and is barrel vaulted, as is the nave. Layers of faded wall paintings are visible on the nave wall. They include a coloured geometric pattern (the earliest) and three paintings of the Ten Commandments (written in Welsh and English), and are thought to date from the thirteenth through to the seventeenth century. In 1739 many of the windows had been blocked, and the nave north window was still blocked in 1861, at which time the church had recently been re-seated. By 1877 the window had been unblocked. The chancel was rebuilt in 1878-1879, to the designs of Clapton Crabbe Rolfe, Oxford. The south and west nave walls were re-fenestrated, the nave was re-seated and the rood loft doorway was blocked. The church was again restored in 1900-1901, under the auspices of the Society for the Protection of Ancient Buildings (SPAB), to the designs of Philip Webb (architect of William Morris's Red House) and William Weir. Repairs in 1900-01 instigated by the agent for the Westmead estate, G.G.T. Traherne were carried out by William Weir (SPAB's architect). Bath stone copings were replaced with limestone, and the building was re-roofed in grey Whitland Abbey slate (since replaced in twentieth century blue slate) Stone ridge tiles (partly removed since) were added to the nave roof. The oak seating, cupboards and chest, in Arts and Crafts style, date to this time. The stained glass, by F. C. Eden, dates to 1906 and 1917. It is in a range of medieval styles, and is considered of exceptional quality.

Sources include:
Cadw, Listed Buildings Database
Cambria Archaeology, 2000, Carmarthenshire Churches, gazetteer, 48
Lloyd, T, Orbach, J and Scourfield, R, 2006, The Buildings of Wales: Carmarthenshire and Ceredigion

RCAHMW, 13 November 2007.