Severndroog Castle is a folly designed by architect Richard Jupp, with the first stone laid on 2 April 1784. While commonly referred to as a castle due to its turrets, it was built as a folly, as can be discerned by its small size and because it has never functioned as a castle. It is situated in Oxleas Wood, on Shooter's Hill in south-east London in the Royal Borough of Greenwich.