Ross Dam is a 540-foot (160 m)-high, 1,300-foot (400 m)-long concrete thin-arch dam across the Skagit River, forming Ross Lake. The dam is in Washington, United States, while Ross Lake extends 23 miles (37 km) north into British Columbia, Canada. Both dam and reservoir are located in Ross Lake National Recreation Area, bordered on both sides by North Cascades National Park.
Built as part of the Skagit River Hydroelectric Project by Seattle City Light, the dam is part of a cascade of three dams through the Skagit Gorge that were built primarily to generate hydroelectricity from the massive elevation drop of over 1,000 feet (300 m) from the Canada-U.S. border to Newhalem. The other two dams are Diablo Dam, directly below Ross Dam, and Gorge Dam, further downstream. Ross Dam generates 460 mW of electricity.