Shell Island, also known as
Mochras, is a
peninsula lying west of
Llanbedr in
Gwynedd, Wales. It was formed after the
River Artro was diverted by
the Earl of Winchelsey in 1819 from its previous course where it entered the sea to the south of Shell Island. Prior to this, access to the ancient settlement on the island would have been through the village of
Llandanwg, which is now across the estuary.