Most of the forest's lakes are the result of glaciation and occur in the SNRA in the Sawtooth and White Cloud Mountains, but lakes can be found in most of the other mountain ranges of the forest. There are over 20 lakes in the Fairfield District, 90 in the Ketchum District, and 6 lakes and 3 reservoirs in the Minidoka District. The largest lake on the forest is Redfish Lake, a moraine-dammed lake that is long, wide, and up to deep. Other large lakes include Alturas, Pettit, Sawtooth, Stanley, and Yellow Belly lakes.