Coordinates: 54°30′36″N 2°48′36″W / 54.510°N 2.810°W
Mardale /mɑːrdeɪl/ is a glacial valley in the Lake District, in northern England. The valley used to have a hamlet at its head, called Mardale Green, but this village was submerged in the late 1930s when the water level of the valley's lake, Haweswater, was raised to form Haweswater Reservoir by the Manchester Corporation.
Most of the village's buildings were blown up by the Royal Engineers, who used them for demolition practice. The exception was the small church, which could accommodate only 75 people, and had an all-ticket congregation for its last service. It was then dismantled in April, 1937, stone by stone, and the stones and windows were re-used to build the water take off tower which is situated along the Western shore of the reservoir. Some 97 sets of remains were disinterred from the churchyard and transferred to Shap.Alfred Wainwright protested bitterly about the loss of Mardale in his series of pictorial guides to the Lakeland fells, having first visited it in 1930. The ruins of the abandoned village occasionally reappear when the water level in the reservoir is low.