Junction of Idaho 75 and US 20 to Carey. US 93 to Arco, continuing on US 93 to Junction of US 93 and Idaho 75.

Without a doubt this byway has the most diverse stretch of road in Idaho. You will experience wetlands, the vistas of the high mountain desert, expansive lava flows, and the Lost River Mountain Range boasting nine of Idaho’s twelve highest peaks including the highest peak, Mt. Borah.

The byway features world-class fly fishing on beautiful Silver Creek, a unique rock formation known to the locals as the “Queens Crown” and the Carey Lake Wildlife Management area home to dozens of species of birds and waterfowl. There is Idaho’s first national monument, Craters of the Moon National Monument and Preserve with thousands of acres of lava fields and unique rock formations. In Arco, the “First City in the World to be Lit by Atomic Energy,” you can see a submarine in the desert.

In the magnificent Lost River Valley, there are peaceful miles of agricultural lands in the shadow of the Lost River Mountain Range. The valley narrows and mountains seem to increase in size as you near Mt. Borah and the rest of the “great peaks.” At Spar Canyon you may see wild horses roaming the desert and are reminded of old western movies as you wind through Grandview Canyon.


Two-lane road with some passing lanes. Winter weather can be severe. Check conditions before traveling.

When to go

Throughout the year.

Special attractions

Craters of the Moon National Monument and Preserve; Science and Technology Center in Arco; Silver Creek (world-class fly fishing); Hayspur Fish Hatchery; Carey Lake Wildlife Management Area; Goodale’s Cutoff; King Mountain Hang Glider Launch site; Lost River Museum; Ghost Towns on the Mine Hill; Big Lost River Access; Mackay Dam and Reservoir; Battleground Cemetery; Mt. Borah and High Peaks of the Lost River Range; Grandview Canyon; Land of the Yankee Fork State Park.


Hayspur Fish Hatchery, Craters of the Moon National Monument and Preserve, Mackay Reservoir.