Gwernllwyn Welsh Independent Chapel was built in 1863-4, and later rebuilt/modified in 1903. It is in the Classical style, with round-headed openings, a painted and stuccoed exterior and pitched slate roof with bracketed eaves. The chapel has a tripartite gable facade with pilasters and a major central arch breaking into the pedimented gable. The central arch contains an arched doorway with pilasters, moulded arch and keystone, below a pair of arched windows, with a keyed roundel with date plaque in the apex.The side bays each have long arched windows with stuccoed surrounds. The side bays have four round-headed windows on the gallery level, with slightly squared windows below.
Inside, the chapel has a U-plan gallery with raked seating, ornate cast-iron panels and dentil cornice, mounted on cast iron columns with fluted capitals. Below, the pews form three banks, with the outer banks slanted towards the pulpit. The puplit is approached via two curving stairways with timber balustrades, and has carved panels to the front. On the wall above the pulpit is a decorative plaster arch mounted on pilasters.

Source: RCAHMW Inventory Documents

K Steele, RCAHMW, 20 March 2009