Duffield Castle was a Norman Castle in Duffield, Derbyshire. The site is a Scheduled Ancient Monument.
The rocky site was easy to defend, because it was surrounded by the river in three sides and hard to climb. It is not clear whether the site was inhabited in prehistoric times. The Roman army might have been there to protect the ford nearby where people from Lutudarum Wirksworth passed before joining Rykneld Street at Derventio (now part of Derby) which was N-shaped route for the North Sea ports.
Ancient items of Anglo-Saxons have been found there. They suggest that Saxon Thane named Siward or his relatives might have occupied the site. Also, many Roman or Romano-British pottery has been found, including roof tiles of Roman pattern. Some of them were kept in the Derby Museum, but others kept in the Parish Room were unfortunately lost.