Gibson Reservoir
Gibson Reservoir is a man-made body of water located just south of the Bob Marshall Wilderness, northwest of Augusta, Montana. It forms part of the county line between Teton and Lewis & Clark counties. The reservoir is formed by the concrete arch Gibson Dam and backs water up between a hilly pass for about 3 miles. The water in the dam is initially provided by spring snow runoff and carried there via the North [Fork Sun River] and the South Fork Sun River right after the two join. The reservoir is mainly used for irrigation control.