This byway follows Route 21 from Boise, north to the historic mining town of Idaho City. Then it goes along the South Fork of the Payette River as it climbs northeast and then squeezes between two Idaho wilderness areas (Sawtooth and Salmon-Challis). After crossing Banner Summit (7056 ft.), it descends to the town of Stanley.
We did this route in reverse (Stanley to Boise) to end our trip.