King Charles's Castle

King Charles's Castle crowns a hillside on Tresco, looking across the approaches to New Grimsby harbour and the neighbouring islands. Despite its name, this artillery fort was built during Edward VI's reign, a century before Royalist forces occupied it in 1651. Its commanding position proved less useful for firing at ships far below, and the surviving walls and gun positions illustrate the difficulties of defending these sea routes. Reviewers praise the views and the climb, often linking the visit with Cromwell's Castle lower down the hillside. The castle can only be reached on foot, with a steep path over exposed, heather-covered ground, so wear sturdy shoes and bring what you need. There are no facilities beside the ruins, and visitors should not climb the walls. Dogs are welcome on leads.