Hells Canyon is the reason most people come to Clarkston. The Snake River carved this gorge along the Idaho–Oregon border, dropping 7,993 feet from the surrounding mountains to the river at its deepest point — significantly deeper than the Grand Canyon, and far less visited. The canyon walls are columnar basalt, often vertical, with shelves of grassland and pine where the cliff steps back.
The standard way to see it is on a jet-boat day-trip from the Clarkston marina, run by several local operators. The boats are flat-bottomed, powerful, and can travel against the rapids that close the canyon to ordinary craft. A typical day-trip runs 100 miles round-trip into the wild and scenic stretch above the navigable river, stops for lunch at a remote ranch, and gets back in time for dinner. Multi-day rafting and kayaking trips through the wilderness section can also be arranged. Watch for bighorn sheep on the cliff shelves and golden eagles overhead.