
Hells Canyon is the deepest river gorge in North America, averaging 5500 feet in depth over its 40 mile length, but reaching 7900 feet.
The first reference to the name "Hells Canyon" did not appear until 1895 and it did not become the common name until the 1950s. Up until that time, the most common name was Box Canyon.
The Hells Canyon National Recreation Area contains the gorge and adjoining areas in both Oregon and Idaho.