This portion of the historic Lewis and Clark Trail is a 152-mile drive between Challis, Idaho and Hamilton, Montana. The southern half follows the Salmon River, with some nice twists through canyons on either side of the town of Salmon. It’s a hot, arid area in summer with the occasional shade from trees along the river.
The northern part leaves the river and ascends into the forests and switchbacks of the 7000-foot Lost Trail Pass, forming the border between Idaho and Montana. On the Montana side the road descends through Bitterroot National Forest and arrives at Hamilton, where you can choose to continue on towards Missoula or head onto the gravel of MT38 east to Skalkaho Pass.
While it’s a bit of a long drive when facing the summer heat, it’s one of the best ways to travel north-south through Idaho.