What is the longest river in United States which is named after an animal?

The Snake River is a major river of the greater Pacific Northwest region in the United States. At 1,078 miles (1,735 km) long, it is the largest tributary of the Columbia River, in turn, the largest North American river that empties into the Pacific Ocean. The Snake River rises in western Wyoming, then flows through the Snake River Plain of southern Idaho, the rugged Hells Canyon on the Oregon–Idaho border and the rolling Palouse Hills of Washington, emptying into the Columbia River at the Tri-Cities in the Columbia Basin of Eastern Washington.

The Snake River drainage basin encompasses parts of six U.S. states (Idaho, Washington, Oregon, Utah, Nevada, and Wyoming) and is known for its varied geologic history. The Snake River Plain was created by a volcanic hotspot which now lies underneath the Snake River headwaters in Yellowstone National Park. Gigantic glacial-retreat flooding episodes during the previous Ice Age carved out canyons, cliffs, and waterfalls along the middle and lower Snake River. Two of these catastrophic flooding events, the Missoula Floods and Bonneville Flood, significantly affected the river and its surroundings.

Native Americans have lived along the Snake for more than 11,000 years. Lewis and Clark explored the area. The Nez Perce and Shoshone were the dominant Native American groups in the region. Later explorers and fur trappers further changed and used the resources of the Snake River basin.