Codnor Castle is a ruined 13th-century castle in Derbyshire, England. The land around Codnor came under the jurisdiction of William Peverel after the Norman conquest. The building is registered as a Scheduled Ancient Monument a Grade II Listed Building and is officially a Building at Risk.

Codnor is a village and civil parish in the Amber Valley district of Derbyshire, England. Codnor is a former mining village and had a population of 3,766 taken at the 2011 Census. It is approximately 12 miles from Derby and 14 miles from Nottingham. Codnor forms a built up area with nearby Ripley.