Castle Malgwyn was built for Sir Benjamin Hammet who took over the Penygored tinworks in the 1790s. The house was originally called Ty Mawr Y Gwaith. Built c.1795, the country house (now hotel) is constructed of ubble stone, originally roughcast, with slate hipped roofs and Cilgerran stone corniced end wall stacks. There is a large three-storey five-window front and a central large arched doorway in a plain stucco surround. The windows have red brick heads and slate sills. There is a slate broad step up to 20th century double doors and fanlight. There is a single-storey later 20th century hotel addition to the left.

Reference: Cadw listed buildings database.
RCAHMW, 2009.