Record: 9.64 hm³
Derwent Reservoir is the middle of three reservoirs in the Upper Derwent Valley in the northeast of Derbyshire, England. It lies approximately 10 miles (16 km) from Glossop and 10 miles (16 km) from Sheffield. The River Derwent flows first through Howden Reservoir, then Derwent Reservoir and finally through Ladybower Reservoir. Between them they provide practically all of Derbyshire's water, as well as to a large part of South Yorkshire and as far afield as Nottingham and Leicester.
Derwent Reservoir is around 1.5 miles (2.4 km) in length, running broadly north–south, with Howden Dam at the northern end and Derwent Dam at the south. A small island lies near the Howden Dam. The Abbey Brook flows into the reservoir from the east.
At its full capacity the reservoir covers an area of 70.8 hectares (175 acres) and at its deepest point is 34.7 metres (114 ft) deep.