Idaho’s Sawtooth Scenic Byway

Route description

From Boise, ID-21 climbs northeast through Idaho City, an old gold rush town, and follows the Payette River through pine forests over Banner Summit to Stanley. The road is winding and can close in winter because of snow and avalanches. Stanley is a tiny town on the Salmon River at the foot of the jagged Sawtooth Mountains.

Redfish Lake, a few miles south of Stanley, is a deep alpine lake with beaches, campgrounds and a lodge, and a boat shuttle takes hikers across to trails at the far end. ID-75 then heads south along the Salmon River, climbing over Galena Summit, at over 8,700 feet, where an overlook shows the headwaters of the river. The road descends to Ketchum and Sun Valley, a ski resort where Ernest Hemingway lived and is buried.

From Ketchum, ID-75 and US-20 lead south and east through the high desert to Arco, the first town lit by nuclear power, with a nuclear reactor museum nearby. Just to the west, Craters of the Moon National Monument has black lava fields, cinder cones and lava tube caves along a loop road. The free permit for the caves is available at the visitor center.

Nights at Stanley can be cold even in summer, so bring warm clothes. The lava fields at Craters of the Moon get very hot in summer, so bring water and walk early in the day. The best time for this route is from late June to September, when the passes are clear of snow.