Porth Hellick

Porth Hellick (Cornish: Porth Helyk, meaning willows cove) is a tidal inlet on the south coast of St Mary’s, the largest island in the Isles of Scilly.

The bay is delineated to the south by a headland known as the Giant’s Castle, which is an Iron Age cliff fort, and Porth Hellick Down and Porth Hellick Point to the north. At low tide a wide expanse of sand and rocks are exposed and a bar of fine shingle provides a barrier from the sea to form the largest area of (usually) fresh water on St Mary’s. A stream rises in Holy Vale and flows south through Higher Moors to the sea at Porth Hellick. In its half-mile length it falls less than 25 feet and has barely cut a river bed through the marsh; but feeds the pool with fresh water.

The area is an important feeding station for migrating and wintering birds and was designated as the Higher Moors and Porth Hellick Pool (St Mary's) Site of Special Scientific Interest (SSSI) for the ″wide diversity of habitats with several rare and notable plant species″ in 1971. All of the land designated as the Higher Moors and Porth Hellick Pool (St Mary's) SSSI is owned by the Duchy of Cornwall.