Ross Lake is a large reservoir in the North Cascade mountains of northern Washington state, United States, and southwestern British Columbia, Canada. The lake runs approximately north–south, is 23 miles (37 km) long, up to 1.5 miles (2.5 km) wide, and the full reservoir elevation is 1,604 feet above sea level.

The Skagit River is a river in southwestern British Columbia in Canada and northwestern Washington in the United States, approximately 150 mi (240 km) long. The river and its tributaries drain an area of 1.7 million acres (690,000 hectares) of the Cascade Range along the northern end of Puget Sound and flows into the sound.