Mynydd-Bach Independent Chapel was first built in 1762 and enlarged in 1797. The chapel was rebuilt in 1865, in the Classical style of the gable-entry type, to the design of architect John Humphreys of Treforest.The front elevation has a hipped porch with corner pilasters and a round windw, which appears to be a later addition to the building. The main facade is divided into three bays by pilasters supporting a broken cornice over which is a giant arch. Within the central bay, over the added porch, is a venetian window with small pane glazing and a small stone plaque inscribed with the name and dates of the chapel phases. To the outer bays are two tiers of falt headed windows, originally with small paned glazing, but with some having replacement upvc windows.

RCAHMW, April 2008.