Reid Lake, also known as Duncairn Reservoir, is a man-made reservoir situated in the southern fishing zone of Saskatchewan, Canada, near the city of Swift Current. Formed in 1942 with the construction of the Duncairn Dam along a glacial meltwater channel on Swift Current Creek, the reservoir was originally developed to supply water to Swift Current, support irrigation projects, and regulate downstream creek levels. The lake covers approximately 3,690 acres with a shoreline stretching 54 kilometers and reaches a maximum depth of 10.4 meters (34 feet). The entire lake falls within the Duncairn Reservoir Migratory Bird Sanctuary, giving it a dual identity as both a productive fishery and a protected wildlife habitat.