Further north in Shoshone, US-93 connects with the southern terminus of State Highway 75, the former route of US-93 to Ketchum and over Galena Summit (8,701 feet (2,652 m) above sea level) to Stanley and Clayton.

This section provides views of the Lost River Range to the northeast of the highway, including Borah Peak, the highest point in the state at 12,662 feet (3,859 m).

The highway crosses the Willow Creek Summit at 7,161 feet (2,183 m) (web-cam) and later descends into Grand View Canyon and heads into the city of Challis.

The highway exits Idaho at Lost Trail Pass (web-cam) at 7,014 feet (2,138 m) and enters Montana toward the Bitterroot Valley.

West of the highway at the pass is the Lost Trail Powder Mountain ski area, with terrain in both states.