At river mile 247, the dam impounds Hells Canyon Reservoir; its spillway elevation is 1,680 feet (512 m) above sea level.

The Hells Canyon Dam powerhouse contains three generating units, with a total nameplate capacity of 391 megawatts (MW).

Lacking passage for migrating salmon, the three dams of the Hells Canyon Project blocked access by anadromous salmonids to a stretch of the Snake River drainage basin from Hells Canyon Dam up to Shoshone Falls, which naturally prevents any upstream fish passage to the upper Snake River basin.

[4] The proposals for a publicly built high dam became a big political issue in many Western states.

Both of Oregon's senators Wayne Morse and Richard L. Neuberger proposed a public dam, but were blocked.