The Snake River
The Columbia's largest tributary, carver of Hells Canyon
The Snake River is the largest tributary of the Columbia, running about 1,078 miles (1,735 km) from the mountains near Yellowstone across the wide volcanic plain of southern Idaho and on to its meeting with the Columbia in Washington. It arcs across the Snake River Plain in a great curve, watering the irrigated farmland — Idaho's famous potato country — that the dry plain could never support on its own.
Along the Oregon–Idaho border the river has cut Hells Canyon, the deepest river gorge in North America, plunging more than 7,900 feet from rim to water, deeper in places than the Grand Canyon. Like the Columbia it feeds, the Snake is heavily dammed for power and irrigation, and the dams' effect on its once-great salmon runs has made the river a focus of long-running restoration debates.