Former Smithy Range at Plas-yn-Cefn

The former smithy range at Plas-yn-Cefn dates from the early 19th century and is constructed of limestone rubble. It features distinctive later 19th-century stepped gable parapets, a squat brick chimney, and a slated roof. The main block has a nearly central entrance that includes a recessed modern boarded door set within a brick cambered arch. To the right of the entrance, there is a double window with one window above the other, both having cambered heads. To the left, there is a squat, unglazed window.

The building also has an upper loading bay with a boarded door on the eastern gable, which has been enlarged in the 20th century, and an open pegged entrance on the western gable. Attached to the southwest is a small single-storey extension from around 1900, which features a squat brick furnace chimney on the western gable end, a corrugated iron roof, and an open front with two bays and a dividing wooden post. The interior is plain.