This is an article on the 18th century building situated on St Peter's Suare. For the 13th century castle, see Ruthin Castle. Castle Hotel is a Grade II* listed building in the community of Ruthin, Denbighshire, Wales. It is in St Peter's Square, which is in the centre of the town. It was listed by Cadw (Reference Number 917).The building is a 3-storey brick construction dating back to the early 18th century.