Description Settled In The Mountains, Hwy 75, Big Wood River, Boulder Mountains, IDState Highway 75 is a two-lane highway that travels through the Sawtooth Valley of central Idaho. The highway's southern terminus is in Shoshone, and its northern is near Challis. It is designated as one of Idaho's scenic byways and provides access to Sawtooth National Recreation Area. It primarily follows the Big Wood River in the south and the main Salmon River in the north, divided by Galena Summit.State Highway 75 begins at a junction with US-93 on Greenwood Street in Shoshone at an elevation of just under 4,000 feet (1,220 m) above sea level. The highway heads northward, and ascends the Big Wood River valley, into Blaine County, past the Magic Reservoir to the west and crosses US-20 at Timmerman Junction at 4,884 feet (1,489 m).It continues northward as the Sawtooth Scenic Byway[2] to pass through the Big Wood River communities of Bellevue, Hailey, and Ketchum. Sun Valley is accessible via a spur route junction in Ketchum at Third Street, which becomes Sun Valley Road.Seven miles (11 km) north of Ketchum, the highway passes by the headquarters of the Sawtooth National Recreation Area at 6,250 feet (1,905 m) and the Boulder Mountains to the north, with peaks over 11,000 feet (3,350 m). SH-75 climbs past the Galena Lodge to the Galena Summit at 8,701 feet (2,652 m), then descends to the scenic viewpoint about a mile later, which overlooks the Sawtooth Mountains to the west and headwaters of the Salmon River in the Sawtooth Valley.Highway 75 descends the grade and reaches the upper end of the valley floor at new Sawtooth City at 7,190 feet (2,192 m), and then enters Custer County. It runs northward down the valley with the Salmon River to Obsidian and Stanley, with the Sawtooths to the immediate west and the White Cloud Mountains to the slightly more distant east. The turnoff to picturesque Redfish Lake is about five miles (8 km) south of Stanley.Wikipedia