Llantrisant Church is located within a small, square churchyard, measuring some 46m x 50m. Llantrisant was the site of the upland chapelry of Llafihangel-y-Creuddyn parish during the medieval period, belonging to the Deanery of Ultra-Aeron. It was abandoned in 1833 due to the construction of a new church nearby but was brought back into use in the later nineteenth century to serve the nearby Frongoch lead mines. The church has three cross-incised stones (NPRN 402331), two in the churchyard and one in the Church.

The current church is thought to be the third church to be erected on this site. Its predecessor is depicted as a ruin on 1834 Ordnance Survey mapping, after being abandoned around 1803, when the nearby church at Eglwys Newydd was built. Earthworks north and west of the church could inidcate debris from the previous structures.

The church, constructed of local rubble stone (hidden beneath external render) was rebuilt in the nineteenth century on the same site and in the same location as its predecessor. It consists of three bay chancel, four bay nave, south porch and west bellcote. The windows are double, single and triple lanclets. The construction materials originate from local rubble and are hidden beneath an external render.

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

K Briscoe, RCAHMW, 4th September 2013