Gorge of the Snake River in the U.S. Forming part of the Idaho-Oregon boundary, it is 125 mi (200 km) long and for 40 mi (64 km) is more than a mile deep.
A maximum depth of 7,900 ft (2,400 m) makes it the deepest gorge in North America. With its surrounding area of 662,000 acres (268,000 hectares), Hells Canyon was designated a national recreation area in 1975.