The Snake River is a river in the U.S. states of Wyoming, Idaho, Washington and Oregon. It is a tributary of the Columbia River. The river rises in western Wyoming, and flows through the Snake River Plain in Idaho. It turns north, forming the border with Oregon and Idaho, and the border with Washington and Idaho. At Lewiston it turns west and flows through Washington to the Columbia River.
The Shoshone and Nez Perce Indians lived on the Snake River. The Lewis and Clark Expedition was the first American expedition to sight the Snake River. The river later was part of the Oregon Trail. Many pioneers traveled down the river to settle in the fertile Willamette Valley in Oregon.
There are fifteen dams on the Snake River. Some are for hydropower, some for irrigation, and some for navigation.