The Snake River is a major tributary of the Columbia River in the U.S. states of Wyoming, Idaho, Oregon, and Washington. The river's length is 1,040 miles (1,670 km), its watershed drains 108,000 square miles (280,000 km2), and the average discharge at its mouth is 56,900 cubic feet per second (1,610 m3/s). The river flows from its source in Yellowstone National Park through a series of mountain ranges, canyons, and plains.