Snake River

The Snake River, at 1,038 miles (1,670 km) in length, is the Columbia River's main tributary. The Lewis and Clark expedition (1803-6) was the first major U.S. exploration of the river. Once known as the Lewis River, the Snake originates at Yellowstone National Park in NW Wyoming, flows through Jackson Lake in the Grand Teton National Park, through Idaho where it cascades down several notable falls. After many twists and turns it finally joins the Columbia River near Pasco Washington.

Tributaries of the Snake include Henrys Fork River, the Boise River, the Salmon River, and the Clearwater River.

The Snake River's many hydroelectric power plants are a major source of electricity in the region. Its watershed provides irrigation for various projects, including the Minidoka, Boise, Palisades, and Owyhee projects by the U.S. Bureau of Reclamation, as well as a variety of private projects such as at Twin Falls.

The Snake runs through a number of gorges. The gorges include one of the deepest in the world, Hell's Canyon, with a maximum depth of 7,900 feet (2,410 m).