Twr-Gwyn Methodist Chapel was built in 1854 by George Northcroft (architect) and Thomas Evans (builder) of Bangor, and then refronted in 1865 by architects Kennedy and Rogers. The present chapel, dated 1865, is built in the Classical style of the gable-entry type and is now Grade II listed. the current facade consisted of three bays of snecked stonework with ashlar dressings, the centre bay advanced and topped with a pediment. Internally there was a sedd fawr enclosed by brass railings and an organ loft, which have both been removed in recent refurbishments together with the fixed pews in favour of flexiable seating. The gallery, originally to three sides of the auditorium, has been truncated to the rear of the building, but the surviving sections retain it wood panelled front, clock and open pews. The ceiling has a central rose surrounded by octagonal panelling and plaster decoration. To the rear is a large vestry with timber panelled ceiling, while the netrance lobby contains a stained glass window commemorating the First World War.

In 2003 Twr-Gwyn was purchased by Penrallt Baptist Church and was subsequently renamed (from NPRN 6701).

RCAHMW, April 2012