From the busy little watersports and ski resort of McCALL, 110 miles north of Boise, Hwy-55 climbs steadily to merge with US-95 and follow the turbulent Little Salmon River. Just south of the hamlet of Riggins, thirty miles on, comes a good opportunity to see Hells Canyon from Idaho. With an average depth of 5500ft this is the deepest river gorge in the US, though you wouldn’t guess so due to its broad expanse and lack of sheer walls. Nevertheless, it is impressive, with Oregon’s Wallowa and Eagle Cap ranges rising behind it and the river glimmering far down below. Heaven’s Gate Overlook is the best viewpoint into the canyon from Idaho; from the south end of Riggins, allow a half-day to reach the overlook on a very steep and winding gravel road (Forest Road 517), best tackled in a 4WD. The canyon is also accessible by road from Oregon and by jet-boat trip.