Penninis Head is the southernmost tip of St Mary’s, the largest of the Isles of Scilly, an archipelago of islands off the south-west coast of Cornwall in England. It lies within the Isles of Scilly Area of Outstanding Natural Beauty and is part of Cornwall’s Heritage Coast; additionally, it is designated a Site of Special Scientific Interest for its geological and biological interest.
Among these are a series of rock formations, granite rocks which have been eroded by the elements into fantastical shapes. Tooth Rock lies on the path that runs towards the Peninnis Lighthouse and is so called for its appearance, which resembles a tooth. Other named rock formations en route to the lighthouse include the Witch’s Head, Pulpit Rock and the Laughing Old Man.