Costa Head is a prominent headland on Eynhallow Sound on the northwestern coast of the Orkney Mainland, Scotland.[1] The tidal indraught of Eynhallow Sound is "scarcely felt beyond a line joining Costa Head and the Reef of Quendale".[2] To the east is the Point of Hellia on which is located the Broch of Gurness, an Iron Agepromontory fort. Gurness' drystone construction of the "round tower fort is flanked by a number of ancillary structures and impressive concentric ditch and rampart outer defences; moreover, the rocky shorelinecliffs posed a formidable approach for marine invaders."[3]
