The Owyhee River, in the southeastern corner of Oregon, is a 280-mile-long tributary of the Snake River. It flows northward from its Nevada headwaters through Idaho, cuts through the arid uplands of southeastern Oregon, and flows into the Snake River on the Oregon-Idaho state line near Adrian. Much of the river flows through a remote and almost unpopulated area.

In 1819, three Owyhees (Natives of the Hawaiian Islands) were detached from Donald McKenzie's Northwest Company's expedition to trap on the river. When McKenzie came back to meet them the next spring, he learned they had been killed by a band of Bannock Indians. The river and the country around it were named Owyhee for these men.

Sometimes referred to as Oregon's Grand Canyon, the river has deep and spectacular canyons that reveal 14 million years of geologic history and numerous archaeological and historical sites.The river also offers a variety of recreational activities, including whitewater rafting and kayaking, hunting, fishing, and exploring. The river canyons are home to mountain lion, bobcat, pronghorn antelope, mule deer, a variety of raptors, and the world's largest herd of California bighorn sheep. In 1984, 120 miles of the Owyhee was designated a Wild and Scenic River.

The Owyhee Dam near the river's mouth (completed in 1932) is a key feature of the U.S. Bureau of Reclamation Owyhee Project, which furnishes irrigation to a large area of eastern Oregon and southwestern Idaho. This project has allowed for the very successful cultivation of potatoes, but it has also meant the disappearance of salmon and summer steelhead from the river and its tributaries.