St Mabon's church is located on high ground below Mynydd Eglwysilan, at the junction of the two roads leading south from Nelson. A medieval site, a church is shown here on Llanfabon Tithe Map 1842, but the rebuilding in 1847 by John Prichard appears to have been virtually complete. It was his first independent commission, having taken on responsibility for the restoration of Llandaff Cathedral Lady Chapel in 1845. The churchyard has been extended to the north and then again as a cemetery on other side of the lane.
The church is small, in Romanesque style, and built of partly snecked narrow-coursed rubble with ashlar dressings, some tooled, and a Welsh slate roof with ashlar copings. Its plan comprises a single-celled nave, relatively large south porch, a small north vestry and a small chancel. The west front is surmounted by a bellcote with a single bell within a Romanesque-style arch under a gable with cruciform finial. The the west gable entrance is tall and round arched, decorated with Romanesque-style motifs. The corners of the building have wide and flat buttresses with coping. The south porch is tall and wide gabled with moulded kneelers, and a high, round-arched doorway; and inside are a flag floor, stone benches and steps up to a shouldered doorway. The south side of the nave has a four-window range of small round-headed windows with simple Romanesque-style mouldings to the heads.
The interior is rendered with exposed dressings and is dominated by the wide Romanesque-style arch with attached shafts and moulded capitals with foliage interlace motif. The roofs are open with arch-braced trusses supported by corbels, six bays to nave and three to the chancel. Other features include deep splays to the windows, flag floor to nave central aisle, a large font enriched with carvings of leaves, birds and stars (probably by Prichard), and stained glass by R J Newbery including three lights of the east window.
The church is set in a walled rectangular churchyard which contains many well-lettered nineteenth-century headstones in Welsh and English, and some monuments retaining very decorative iron railings.

Source: extracts from Cadw Listing description

RCAHMW, 23 December 2014