Plas yn Rhiw is an early 17th-century manor house in Y Rhiw, Gwynedd in northwestern Wales. The estate consists of a small house of Tudor/Georgian style, a garden of just under one acre in size, and many wooded acres. Located at the base of Mynydd Rhiw, the estate overlooks the beach of Porth Neigwl (Hells Mouth), Cardigan Bay, and the Llŷn Peninsula.