Sun Valley to Dillon: Epic Idaho-Montana Road Trip Guide

This route begins in Sun Valley, Idaho, at the base of Bald Mountain, and ends 280 miles north in Dillon, Montana, near the Pioneer Mountains. Along the way, you'll traverse the Continental Divide twice and cross the historic Bannock Pass, a route used by Native American tribes and pioneers. The drive takes about 5 hours without stops, but plan for a full day to soak in the scenery.

The journey spans three major highways: ID-75 north from Sun Valley, US-93 from Challis to Salmon, and then ID-28 and MT-324 into Dillon. Among the best stops Sun Valley, ID to Dillon, MT are the Craters of the Moon National Monument and the ghost town of Gilmore. For those wondering how long to drive Sun Valley, ID to Dillon, MT, expect 5 to 6 hours of pure driving time. But is it worth driving Sun Valley, ID to Dillon, MT? Absolutely—this is one of the most scenic and underrated routes in the Intermountain West.

Fuel up in Sun Valley, Challis, Salmon, and Dillon. Stretches between Challis and Salmon are sparse. The route is mostly two-lane highway with mountain passes; cell service is intermittent north of Challis. Download offline maps before departure.

• Gas stations: Sun Valley (multiple), Challis (3 stations), Salmon (several), Dillon (abundant).
• Passes: Bannock Pass (7,664 ft) and Chief Joseph Pass (7,241 ft). Both are paved but can be narrow and winding.
• Weather: Summer highs 80s, winter snow possible Oct-May. Check road conditions at idahoroads.com and mdt.mt.gov.

For those planning things to do between Sun Valley, ID and Dillon, MT, consider a detour to the Craters of the Moon National Monument (30 miles west of ID-75). Entrance fee $20 per vehicle. Also, the Sacajawea Interpretive Center in Salmon offers free admission. Learn more about how to find the best stops and hidden gems between cities.

Road quality is generally good but watch for loose gravel on shoulders and occasional wildlife (deer, elk). Summit passes may have ice even in spring. Restrooms: every 20-30 miles in towns, but also at trailheads like the Goldbug Hot Springs trailhead (south of Salmon). Cell service: none from Challis to just before Salmon. Carry a paper map or GPS with offline capability.

Family and child suitability: high. Kids enjoy the Moon Craters tram tour, the Salmon River jet boat rides (Idaho Adventures), and the Bannock State Park fossil dig. Pet-friendly framework: most outdoor attractions allow leashed dogs. Craters of the Moon permits pets on paved trails. Fatigue management: break at the Salmon Valley Rest Area (ID-28 mile marker 25) with picnic tables and views. Local culture: each town has a museum—try the Lemhi County Historical Museum in Salmon.

The route transitions from the granite peaks of the Sawtooth National Recreation Area to the sagebrush steppe of the Lemhi Valley. Craters of the Moon features lava tubes and cinder cones—a UNESCO World Heritage candidate. Further north, the Salmon River Canyon offers jaw-dropping vistas. The Pioneer Mountains near Dillon are a lesser-known gem for hiking and fossil hunting.

Local commerce thrives in small towns. In Challis, the Challis Hot Springs offer a soak for $10. Salmon boasts the Salmon River Brewery with local craft beers. Dillon’s weekly farmers market (summer Saturdays) showcases Montana-grown produce and artisanal cheeses. For hidden off-route spots, visit the ghost town of Gilmore (off ID-28, unpaved road) with well-preserved buildings from the 1880s mining boom.