There are substantial remains of Rhuddlan Castle, a masonry castle established with a borough (NPRN 15238) in 1277, replacing an earlier castle site at Twt Hill (NPRN 157156). It was demolished in 1648.
The castle is based on a quadrilateral, towered inner court, approximately 43m square, within a roughly concentric outer enclosure. It is bounded by a broad stone-revetted moat, except where it rests on the river bank on the south-western side. It is associated with town defences to the north-west (NPRN 300415) and possible Edwardian defences to the south-east (NPRN 306672).
