About 1,080 miles · WY, ID, OR, WA · source Yellowstone NP · mouth Columbia at Pasco
Snake River map
The Snake flows about 1,080 miles from Yellowstone National Park across southern Idaho to the Columbia in Washington, cutting Hells Canyon, the deepest river gorge in North America, on the Idaho–Oregon border.
Where the Snake is
The Snake rises on the Two Ocean Plateau in the southern part of Yellowstone National Park, Wyoming, flows south through Jackson Hole beneath the Tetons, and enters Idaho at Palisades Reservoir. It then makes a 400-mile arc across the Snake River Plain of southern Idaho, turns north to form the Idaho–Oregon border through Hells Canyon, briefly forms the Idaho–Washington border at Lewiston, and swings west across southeastern Washington to join the Columbia near Pasco. It is the Columbia's largest tributary and about 1,080 miles long.
States along the river
- Wyoming — source, Jackson Lake and Jackson Hole.
- Idaho — Idaho Falls, Twin Falls, the Magic Valley and the western border; Boise is on the Boise River, a tributary, about 40 miles from the Snake.
- Oregon — the eastern border along Hells Canyon.
- Washington — Clarkston, then the lower Snake and its four dams to the Columbia.
Tributaries also drain parts of Nevada and Utah, so the basin touches six states.
Key measurements
- Length: about 1,080 miles; basin about 108,000 square miles.
- Hells Canyon, between Idaho and Oregon, is about 7,900 ft deep from He Devil peak to the river, deeper than the Grand Canyon.
- Shoshone Falls near Twin Falls drops 212 ft, higher than Niagara.
- Idaho's high desert plain is a volcanic lava surface; the river has cut a canyon into it that is 500 ft deep at Twin Falls.
- Dams: Jackson Lake, Palisades, American Falls, Hells Canyon, Oxbow, Brownlee, and the four lower Snake dams (Ice Harbor, Lower Monumental, Little Goose, Lower Granite) that make Lewiston a seaport 465 miles from the ocean.
Cities on the river
Jackson, Wyoming; Idaho Falls, Pocatello (nearby on the Portneuf), Twin Falls, and the farm towns of the Magic Valley; Ontario, Oregon; Lewiston, Idaho, and Clarkston, Washington, twin towns named for the explorers; and the Tri-Cities at the mouth. Boise, the largest city in the basin, lies in the Treasure Valley north of the river.
How the river shaped the map
Almost all of Idaho's population lives along the Snake River Plain, which is why the state's cities form a crescent from Idaho Falls to Boise. The river is the border between Idaho and Oregon for about 200 miles, and Oregon's northeastern corner is defined by it. The Oregon Trail followed the Snake across Idaho to Fort Boise and then crossed to the Columbia. The Snake also carries water from the Wind River and Teton ranges of Wyoming west across the Continental Divide, in the sense that its source is only a few miles from the Yellowstone River, which flows east to the Missouri.
Related maps
- Columbia River — where the Snake ends.
- Yellowstone — where it begins.
- Rocky Mountains · Pacific Northwest states.
- Longest US rivers · All geography maps.