Mill and Waterwheel, with attached Stables, at Trefarthen

The building is a farm mill with an attached stable located at Trefarthen. It is a two-storey structure with a waterwheel pit at the rear and a single-storey stable on the south side, forming an L-shape. The mill features a three-window range with rubble walls and a hipped slate roof. On the ground floor, there are doors at both ends and two windows in between, with the window heads raised above the level of the doors. The first floor has three 9-pane windows, all with slate lintels and sills. Access to the first floor is via external stone stairs with brick treads located on the right end wall.

At the rear of the building is a subterranean waterwheel pit, now covered, which once housed an intact 18-foot waterwheel that powered agricultural machinery. The stable attached to the south side has four bays and was designed for six working horses, featuring rubble walls and a pitched slate roof. The left door has been widened for vehicle access, with a door and window on the right, both having slate sills.

Inside, the stable has a three-bay sawn and bolted king-post roof truss. There are also remains of a bearing that supported machinery in the rear wall of the ground floor.