Derwent Reservoir is the middle of three reservoirs in the Upper Derwent Valley in the northeast of Derbyshire, England. It lies approximately from Glossop and 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.