St John's church is prominently sited on high ground above Penamser Road, in a large sloping churchyard at the west edge of the town centre. It is a geometrical style parish church built 1873-6 to designs first of local architect Thomas Roberts, then by Axmann and Perrott of London.
The church is constructed of snecked, rock-faced Deudraeth stone with Bath stone dressing and cornices and red sandstone banding, and slate roof behind coped gables. Its ground plan comprises an aisled nave, lower and narrower chancel, north-west tower and south vestry and organ chamber. The buttressed west front has an entrance in a slightly advanced steep coped gable.
The aisle windows are two-lighters with quatrefoils alternating with stepped three-lighters, all cusped, and similarly elaborate east and west windows, and all with stained glass. The tower, three-staged and added in 1898, stands detached from the nave. It has angle buttresses and bold octagonal corner turrets.
The interior is spacious with an eight-bay roof of arch-braced trusses alternating with kingpost trusses with tie, collar and semi-circular arch braces. Other interior features include a square freestone font rounded at the angles, on a round stem with detached polished stone shafts at the angles, to a moulded base, and polished stone plinth; and a large polygonal wooden pulpit standing on posts, with two tiers of decorated panels.
The chancel has been converted to a meeting room.

Sources: extracts from Cadw Listing database
Haslam et al., Buildings of Wales: Gwynedd (2009), p.498-9.

David Leighton, RCAHMW, 18 November 2014