Capel-y-Graig was built to house a community founded in 1670, making it one of the earliest in the region. The first meeting house on this site was built in 1703, and went through a number of stages of rebuiling - in 1750-65, 1791, 1801, and 1827. The chapel is in the round-headed style, built from rubble stone, with cut grey Cilgerran stone voussoirs and keystones and cemented sills, topped by a hipped slate roof with paired brackets to the eaves. The building is entered via panelled doors with traceried fanlights in paired gabled porches in the long wall, between which are two long arched windows with twentieth century coloured lead glass replacing earlier small-pane glazing. To either side of the porches are a pair of small-paned rectangular windows, with two small copies of these to the upper storey. The side elevations have ususual external stone stairs leading to the gallery. To the rear of the chapel is a brick outbuilding, and to the right of the right-hand external staircase is a schoolroom.
Within the chapel is a three-sided gallery mounted upon cast-iron columns, one of which bears the date 1827. The chapel is noted for its fine painted grained woodwork, which can be seen on the gallery front and the three banks of panelled box pews. The ceiling has an unusually large moulded plaster decoration of plant-scroll motifs and flowers.

Source: Cadw Listed Building Record and RCAHMW Inventory Documents

K Steele, RCAHMW, 17 February 2009