Plas Gwyn including Plas Bychan

Plas Gwyn, which includes Plas Bychan, is a house from the mid-18th century that has been altered over time. The exterior is roughcast with stucco dressings, featuring a slate roof with close eaves and roughcast external end stacks. The gables have stone coping on moulded kneelers. The house is two storeys high with an attic and has a three-window range, accented by rusticated quoins. The earlier 20th-century metal windows are set in the original openings and consist of triple casements with small-paned top-lights. The openings are cambered-headed, adorned with painted stone rusticated voussoirs and triple keystones. The central door is framed by a painted stone shouldered architrave, frieze, and pediment, although the door itself is from the 20th century. A doorstep is inscribed with a height of 864 feet (263 meters) above sea level.

On the eaves, there are three pairs of small timber dormers with carved wood crestings, all from the 20th century. To the right of the main house, there is a single-storey addition that features three large square small-paned windows and a door situated between the first and second windows, along with a roughcast right end stack. To the left, a rubble stone garden wall includes a blank window and two doors. The rear of the house is windowless on the right side, while a rear wing on the left has a roughcast end stack, a coped gable, and a one-window range facing north. This wing has a French window on the ground floor, a triple casement above, and similar eaves dormers as those on the front. Beyond this, the lower wing has been converted into a separate dwelling, Plas Bychan, which features small-paned casement windows, similar dormers, and a hipped-roofed porch.

Inside, it is said that there is an 18th-century staircase with turned balusters and panelled doors.