Church of St Mary, Llanfair-yn-Cwmwd

The Church of St Mary, Llanfair-yn-Cwmwd, is a simple rectangular Medieval church, dating to the Medieval period. The church comprises a nave and chancel that are structurally undivided. The walls are constructed of local rubble with sandstone dressings. It has a slate roof, topped with a single rubble-built bellcote with a slate capping at the west gable end. The north wall features an entrance through a round-headed arched doorway at the west end, and a pair of segmental-headed leaded lights towards the centre. The south wall has two windows with paired leaded lights; the western window has round heads, while the eastern window has segmental heads. The chancel window has paired trefoil-headed lights.

The church's roof is composed of 7 bays, exhibiting exposed rafters and collared trusses, with arched collars that have chamfered soffits. The chancel is raised by one step and separated from the nave by a 19th-century wooden screen of three bays. The lower portion has central wrought-iron gates flanked by tongued and grooved panels beneath a quatrefoil-pierced frieze and moulded rail. The upper portion is supported by plain wooden piers, featuring a plain frieze painted with the word "SANCT" in each bay, beneath a moulded rail and chamfered brackets with pierced spandrels. The sanctuary is raised by one step, and the altar base by a further step, both finished with encaustic tiles.

A mid-13th century coffin lid is hung on the north chancel wall, adorned with a cross carved in low relief and a richly floriate head and stem. At the rear of the church is a 12th-century font with an irregular oval bowl rising from a roughly rectangular base. The bowl has a flattened rim decorated with a rough zig-zag pattern, and three sides are decorated with an expanded arm cross (the fourth side being defaced). The base features a human head in relief at each corner, and another in the center of one side, flanked by crosses. Serpents are carved on the east and south faces of the base, the south face having an incised chevron below. A cable moulding runs around the top of the base, continuing on the south side as a zig-zag band.

The nave contains 19th and 20th century memorials, including a slate memorial plaque on the south wall dedicated to Elizabeth, wife of William Humphreys of Sychant, Caernarvonshire, who died in 1780. The bell bears the inscription "+ THIS BEL WAS CAST IN THE YER OF OWER LORD GOD WDLXXXII," accompanied by four stamps, a fleur de lys, and the letters AMN repeated three times.