Salmon to Rock Springs Road Trip: Gems & Routes

Salmon, Idaho, sits at the confluence of the Salmon and Lemhi rivers, while Rock Springs, Wyoming, is known for its fossil-rich Green River basin. The drive spans roughly 460 miles, crossing the Continental Divide twice, and passes through the remote, volcanic landscapes of the Snake River Plain and the high desert of Wyoming.

This route is not just a means to an end; it offers a journey through geological history, from the craters of the Craters of the Moon to the wind-sculpted rocks of the Red Desert. With proper planning, you can uncover hidden gems that rival the famous parks.

Start on US-93 South from Salmon to Challis, then take ID-75 South to Stanley, and finally US-20 East through Craters of the Moon. From there, continue on US-20 to I-84 East, then I-86 East, and I-80 East into Wyoming. Expect to spend 7-8 hours on the road without stops.

Fuel stations are sparse — notably between Arco and Idaho Falls (about 85 miles) and between Rawlins and Rock Springs (about 60 miles). Plan to fuel up in larger towns like Challis, Arco, Idaho Falls, Pocatello, and Rawlins.

Road quality is generally good, but be cautious of winter conditions: pass closures and icy patches are possible. Carry tire chains and a full-size spare.

• Major passes: Galena Summit (8,701 ft) and South Pass (7,414 ft)
• Weather stations: NOAA forecasts for Stanley, Idaho Falls, and Rawlins
• Cell coverage: Spotty; don't rely on GPS in remote areas

Two-lane highways with 55-65 mph speed limits require vigilance. Beware of wildlife, especially deer and elk at dawn and dusk. Keep a safer following distance, especially with RVs.

For rest stops, use designated areas every 2 hours. Key stops: Challis Rest Area (milepost 238 on US-93), Chesterfield Rest Area (near Lava Hot Springs), and Saratoga Rest Area (on I-80).

Family-friendly attractions include the lava tube caves at Craters of the Moon (allow 30 min), the swimming pools at Lava Hot Springs, and the dinosaur tracks at the Wyoming Dinosaur Center in Thermopolis (a slight detour). For kids, the Discovery Center in Idaho Falls offers interactive science exhibits.

• Pet-friendly: Many national parks and rest areas allow pets on leash; check Craters of the Moon's policy
• Family dining: Kid-friendly menus at Sizzler in Rawlins, or Golden Arches in Idaho Falls
• Fatigue tip: Pull over and walk 10 minutes; caffeine at gas stations is available

The route showcases the volcanic basalt of Craters of the Moon National Monument, formed by lava flows as recent as 2,000 years ago. Further east, the Blackfoot and Portneuf ranges frame the drive near Pocatello. In Wyoming, the Red Desert's shifting sands and rock formations like the Haystack Mountains offer a stark beauty.

For a unique perspective, visit the how to find the best stops and hidden gems between cities guide.

Local commerce is dominated by small towns: Challis has old-west charm with its historic courthouse, Arco is the first city in the world to be powered by nuclear energy, and Ferney has a quirky 'seat belt' sign tradition. For dining, try the ice cream at Craters of the Moon's visitor center or local burger joints in Idaho Falls.

• Farmers' markets: Idaho Falls (Saturdays), Rock Springs (Wednesdays)
• Local specialties: Ruby-throated hummingbirds at the Camas National Wildlife Refuge in Hamer
• Cultural sites: EBR-1 in Arco, the first nuclear reactor