Derwent Edge is a Millstone Grit escarpment that lies above the Upper Derwent Valley in the Peak District National Park in the English county of Derbyshire. The Millstone Grit forms the edge of the high peat moorland plateau on the eastern side of the valley above Ladybower Reservoir, the edges being the last remains of the gritstone which originally covered all of the Peak District, most of which was scraped off by glaciers in the last ice age. An Ordnance Survey column marks the highest point of the Edge at Back Tor at a height of 538 metres (1765 feet).