Y Rhiw is a small village on the south west tip of the Llŷn Peninsula in Gwynedd, Wales. The village forms part of the community of Aberdaron.

The Llŷn Peninsula extends 30 miles (50 km) into the Irish Sea from North West Wales, south west of the Isle of Anglesey. It is part of the historic county of Caernarfonshire, and historic region and local authority area of Gwynedd. Much of the eastern part of the peninsula, around Criccieth, may be regarded as part of Eifionydd rather than Llŷn, although the boundary is somewhat vague. The area of Llŷn is about 400 km2 (150 sq mi), and its population is at least 20,000.