The Derwent is a river in the county of Derbyshire, England. It is 80 km (50 miles) long and is a tributary of the River Trent which it joins south of Derby City.
It rises in the Peak District at Bleaklow east of Glossop and flows through the Upper Derwent Valley with its three reservoirs, the Howden Reservoir, Derwent Reservoir and Ladybower Reservoir. It then passes through Bamford, Hathersage, Grindleford and Baslow, and through the Chatsworth Park estate, and it is joined by the River Wye. After passing through Darley Dale, the Derwent reaches Matlock. It flows past Cromford and through the Crich Chase Nature Reserve.
The river was used to power many cotton mills in the Derwent Valley Mills area.
The name "Derwent" is Celtic and means "a valley thick with oaks".
