Idaho has the largest contiguous wilderness in the Lower 48 and quite a few rivers running through it. No matter which pick we make here, one or two classics will be left out. For pure whitewater terror, however, it’s hard to beat the two-day paddle on the free-flowing Lochsa. The continuously explosive, 40 class III-IV rapids—with names like Grim Reaper and Bloody Mary—are the result of both big volume (10-20,000 cfs) and steep gradient (30 feet per mile). This kind of whitewater is akin to more famous rivers, like the Gauley in West Virginia, but the Lochsa is bigger and longer.
For the full Idaho experience, front-load the Lochsa with a five-day paddle on the Snake River through Hells Canyon. With Grand Canyon-style rapids through North America’s deepest river gorge, 70-degree water temperatures, and pictographs and pioneer homesteads along the way, Hells Canyon is awe-inspiring. Seven-day combination, $1,995; best in June.