 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 .It continues northward as the "Sawtooth Scenic Byway" 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.