This article is about the river in the northwestern United States. For other uses, see Snake River (disambiguation).

The Snake River is a major river of the greater Pacific Northwest in the United States. At long, it is the largest tributary of the Columbia River, the largest North American river that empties into the Pacific Ocean. Rising in western Wyoming, the river flows through the Snake River Plain of southern Idaho then through the rugged Hells Canyon area via northeastern Oregon and the rolling Palouse Hills to reach its mouth near the Washington Tri-Cities area, where it continues as part of the Columbia. Its drainage basin encompasses parts of six U.S. states, and its average discharge is over .