Carsington Reservoir is a reservoir operated by Severn Trent Water in Derbyshire. The reservoir takes water from the River Derwent at Ambergate during winter months, pumping up to the reservoir by 10.5 km long tunnels and aqueduct. Water is released back into the river during summer months for abstraction and treatment further downstream. It is England's ninth largest reservoir with a capacity of 35,412 megalitres.

Planning for the reservoir started in the 1960s with actual construction starting in 1979. In 1984 there was a partial collapse of the dam prior to it's filling. The dam was subsequently completely removed before construction of a new commenced in 1989. The finished reservoir was opened by Queen Elizabeth II in 1992.

The reservoir is a major centre of leisure activities including walking, cycling, birdwatching, sailing and windsurfing.