Winscar Reservoir sits on the headwaters of the River Don in South Yorkshire, England, nestled within the Peak District National Park near the village of Dunford Bridge in Barnsley — approximately 25 miles northwest of Sheffield. Built on the Pennine watershed and completed in 1975, it holds the distinction of being the last reservoir constructed on the River Don and the first major dam in England built with an asphaltic concrete membrane on the upstream dam wall. It is one of 25 reservoirs along the River Don's course and remains the only one built under Yorkshire Water's tenure. The reservoir sits in an upland moorland setting, giving it a dramatic and scenic character typical of the South Pennines. Due to the low-supply nature of its catchment, the reservoir takes approximately two years to fully restock after being drained — a reflection of the challenging hydrology of this high moorland environment.