The Derwent rises in the wild country east of Bleaklow, in the heart of the Dark Peak. After somewhat less than five miles, its waters flow into Howden Reservoir, then Derwent Reservoir, and finally Ladybower. From Ladybower, the Derwent runs through down the eastern flank of the Peak District, passing Hathersage, Baslow, Chatsworth and Matlock (amongst many). Outside the Peaks it runs through Derby and finally joins the Trent between Nottingham and Derby. On its way it swallows up the Rivers Noe and Wye, draining a large part of the Peaks.
The most dramatic section of the lower Derwent is the section between Matlock and Matlock Bath, where the river runs through a gorge, forcing the railway into a tunnel. Geologically, the Derwent is a river of the Dark Peak, running down the eastern finger of Millstone Grit that borders the White Peak. It is this Millstone Grit that gives the Derwent Valley its fringe of dramatic Edges (and many of the roads in from the east their sudden dramatic descent).
The River Derwent played an important role in the early years of the Industrial Revolution. In 1771 Richard Arkwright built the first water power cotton mill at Cromford, just south of Matlock Bath, using the power of the Derwent to help make his fortune, transforming the cotton industry on the way.