Derwent (river)

Derwent (river), river in England, a major tributary of the River Trent, and the largest river in the Peak District. Approximately 80 km (50 mi) in length, it rises in the High Peak and drains a large proportion of the county of Derbyshire. The northern section flows down a steep-sided valley enclosed by gritstone moorland, before reaching three man-made reservoirs, the Howden, Derwent, and Ladybower. After leaving Ladybower the Derwent carves its way through a ridge of limestone and joins the River Trent just south of the city of Derby. The 18th- and 19th-century cotton mills in the Derwent Valley, forming a valuable historical and industrial landscape, were named a UNESCO World Heritage Site in 2001.