Hells Canyon

Hells Canyon is a massive river gorge located in the Western United States.

This canyon sits along the borders of eastern Oregon, western Idaho, and a small section of eastern Washington. It is part of the Hells Canyon National Recreation Area. This area also overlaps with parts of the Wallowa-Whitman National Forest. The canyon is North America's deepest river gorge. It is actually deeper than the Grand Canyon in Arizona. The Snake River is the primary force that carved this deep landscape.

The geological history of the canyon began approximately 300 million years ago. At that time, an arc of volcanoes emerged from the Pacific Ocean. Over millions of years, these volcanoes subsided below the water. Limestone built up on the underwater platforms during this time. Sedimentary rock filled the basins between these volcanic structures. Between 130 and 17 million years ago, the ocean plate collided with the North American continent. This collision made the volcanic arc part of the continent. Later, basalt lava floods covered much of the area. These flows smoothed the topography into a high plateau.

Rivers began carving the canyon out of this plateau about 6 million years ago. A major change occurred around 3 million years ago. Water from Lake Idaho overtopped a natural divide. This allowed the Snake River to flow through the plateau. This flow helped carve the canyon even further. However, a 2025 study suggests the canyon might be younger than scientists once believed. This study concludes the canyon began only 1.6 million years ago. Massive outburst floods from Lake Bonneville in Utah also shaped the canyon as recently as 15,000 years ago.

Human history in the canyon is very old. The Nez Percé tribe were the earliest known residents. Other tribes, such as the Shoshone-Bannock, northern Paiute, and Cayuse, also visited the area. They were attracted by the mild winters and abundant wildlife. You can still see pictographs and petroglyphs on the canyon walls today. In 1806, the Lewis and Clark Expedition entered the region. They followed the Salmon River but did not see the deepest parts. In 1811, the Wilson Price Hunt expedition tried to find a shortcut to the Columbia River. They were forced to turn back due to hunger and cold.

Miners arrived in the 1860s after gold was discovered in river bars. While they found gold, mining in the canyon was not very profitable. Some miners later used complex facilities for hard-rock mining. Evidence of these efforts remains near the mouth of the Imnaha River. In the 1880s, a short-lived homesteading boom occurred. Most settlers left because the weather was not suited for farming. A tragic event also occurred in May 1887. This was known as the Hells Canyon Massacre. During this event, 34 Chinese gold miners were ambushed and killed. No one was ever held accountable for this violence.

Today, the Snake River is used to generate large amounts of hydropower. Between the 1930s and 1950s, many dams were built on the Columbia River. This led to requests for dams on the Snake River as well. The Idaho Power Company received a license in 1955 to build a three-dam complex.

The Brownlee Dam was finished in 1960. The Hells Canyon Dam was completed in 1967. The Oxbow Dam was finished in 1972. Together, these three dams have a capacity of 1,167 megawatts. This complex provides about 70 percent of Idaho's hydroelectricity. However, the dams block the migration of salmon and other anadromous fish.

Hells Canyon is now a major destination for outdoor recreation. The Snake River offers many class I-IV rapids for whitewater sports. People enjoy rafting, kayaking, jet boat tours, and fishing. The area is home to over 350 species of wildlife. Visitors can hunt for elk, mountain goats, and black bears. Much of the canyon is wilderness and is inaccessible by road. There are only three roads that lead to the Snake River. These roads are located between the Hells Canyon Dam and the Oregon-Washington state line. Most activities, like whitewater sports, peak during the summer months.