The John C. Boyle Dam is a hydroelectric dam located in southern Oregon, United States. It is on the upper Klamath River, south (downstream) of Keno, and about north of the California border. Originally developed and known as Big Bend, the John C. Boyle dam and powerhouse complex was re-dedicated to honor the pioneer hydroelectric engineer who was responsible for the design of
virtually all of the Klamath Hydroelectric Project.
The Boyle Diversion Dam includes several sections (earth-fill, concrete gravity, intake and spillway) that
combine to form an overall crest length of with a height of . The concrete spillway portion
contains three gates and forms the John C. Boyle Reservoir. Fish screens, fish ladder, and related features are
also present at the site.
The dam produces power at peak times, meaning sometimes it produces electricity and returns water to the river; other times only a small amount of water is returned to the river. This causes a "bathtub" ring effect downstrea