St Mary's Church is located on the site of a medieval church, of which there are records dated 1254. It is situated within an irregularly shaped churchyard, which appears to have once been curvilinear in form. The churchyard has been encroached on by buildings and property walls on all but its west side, which is bounded by a road. In 1792 it was noted to have been extended to the north-west by 10 roods. A window mullion set into the west churchyard wall is probably re-used from the earlier church building. The churchyard entrances are on the south-east and west sides. The church contains a fourteenth century effigy, re-set from the medieval church, of Meurig ab Ynyr Fychan carrying a naked sword. A chantry alter is recorded as having been located in the church in 1558.

The present church, a Grade II listed building, is entirely Early Georgian and a rarity in Wales. It was built in 1716, and is constructed of rubble stone with square stoned voussoirs to the windows and doors. The building consists of a nave and apsidal chapel, north and south aisles and a west tower. The nave is divided from the aisles by arcades of wooden beams. The nave was complete by 1723. With its large arched windows and apse, it is a reduced version of the church in Whitchurch, Shropshire, which was built in 1712. The tower is thought to have been begun in 1727. The church was restored in 1864. The chancel arch dates to this time, which is when the windows of the apse were altered. A central window was inserted in 1901. The western end upper room was added by Roy Olsen of Dolgellau in 1992 and is bow-fronted with arched windows.

Sources include:
Gwynedd Archaeological Trust, 2000, Historic churches of Gwynedd: gazetteer, 391
Haslam, Orbach and Voelcker, 2009, The Buildings of Wales: Gwynedd. Pevsner Architectural Guide, 586.

N Vousden, RCAHMW, 28 May 2012