 The junction is at and Highway 75 northbound becomes the "Salmon River Scenic Byway," continuing north for a mile, then veering east and descending with the twisty river towards Clayton.Both then head north towards Challis, where the route terminates and rejoins US-93 just south of the city limits, at an elevation of .In 1824, while searching the mountain wilderness of what is presentday Idaho, known to them as Columbia District, for beaver, Alexander Ross came up the Wood River and discovered Galena Summit on September 18.