The inner gorge of the canyon is made up of black Precambrian rock and contains class III and IV rapids which are sought after by whitewater enthusiasts.

The Bureau of Land Management (BLM) oversees a permitting system for whitewater travelers for this section of the Colorado River, and boaters must follow special rules and regulations.

Many boaters pack camping equipment in on rafts and make the 17-mile (27 km) trip from Westwater ranger station to Cisco landing over 1–2 days.

The uppermost rocks in the canyon date from the Triassic-Jurassic periods and are composed of the reddish, cliff-forming Wingate Sandstone atop the green to purple, slope-forming Chinle Formation.

Within the inner gorge of Westwater, a large unconformity separates the Chinle Formation from the Precambrian basement rocks composed of metamorphic Vishnu Schist (black) and Zoroaster Granite (pink).