King Charles's Castle is a ruined artillery fort on the island of Tresco in the Isles of Scilly, built between 1548 and 1551 during the reign of King Edward VI to defend against French invasion. Despite its name—derived from its occupation by Royalist forces during the English Civil War in 1651—the fort predates that conflict by a century. Now managed by English Heritage as a scheduled monument and Grade II* listed building, the site offers visitors free access at any reasonable time during daylight hours to explore this historic 16th-century defensive structure with views over the narrow strait and New Grimsby harbour.
