Nottingham Castle is a castle in Nottingham, England. It is located in a commanding position on a natural promontory known as "Castle Rock", with cliffs 130 feet (40 m) high to the south and west. In the Middle Ages it was a major royal fortress and occasional royal residence. In decline by the 16th century, it was largely demolished in 1649. The Duke of Newcastle later built a mansion on the site, which was burnt down by rioters in 1831 and left as a ruin.