Salmon ID to Spearfish SD: A 12-Stop Road Trip Itinerary

Salmon, Idaho sits at the confluence of the Salmon River and the Bitterroot Range, while Spearfish, South Dakota anchors the northern Black Hills. The shortest driving route is roughly 710 miles via I-90 and I-15/84, but the most memorable detour stretches 1,000 miles, crossing six states and two time zones. This is not just a highway hop; it's a traverse of the Continental Divide twice, through the sagebrush steppe, Yellowstone's volcanic plateau, the Great Plains, and finally the granite spires of the Black Hills.

Your journey begins in the 'River of No Return' country, where the Salmon River carves the deepest gorge in the contiguous US. You'll end at the birthplace of the iconic Sturgis Motorcycle Rally, a town named for the Spearfish Creek that once powered gold mills. Along the way, you'll encounter the tallest mountain in Wyoming (Gannett Peak), the largest hot spring in the world (Grand Prismatic), and the only national monument in the US that is a complete mountain (Devils Tower).

The route crosses the Continental Divide at Togwotee Pass (9,455 ft) and again at Powder River Pass. The geology shifts from basalt columns near Idaho Falls to the hydrothermal basins of Yellowstone, then to the red-rock canyons of the Bighorn Basin, and finally the granite needles of the Black Hills. Keep a camera ready for pronghorn, bison, and elk.

Local commerce thrives in small towns like Dubois, WY, known for its rustic boardwalks, and Buffalo, which preserves a western main street with saloons and saddle shops. In the Black Hills, you'll find artisan galleries selling gold jewelry and Native American crafts. The how to find the best stops and hidden gems between cities guide suggests exploring state highways like Alt-14, which parallels I-90 and offers quieter viewpoints.

Don't miss the town of Deadwood, a National Historic Landmark where 'Wild Bill' Hickok was shot in 1876. Its casinos and 19th-century architecture draw crowds, but even a quick stroll through Mount Moriah Cemetery is worth the detour.

Highway 20 through Yellowstone is a two-lane road with occasional wildlife jams. Maintain a safe distance from bison and allow extra time for photo stops. In winter, carry chains; in summer, watch for sudden thunderstorms on the high plains.

For families, the route includes the Yellowstone Bear World (Rexburg), the Buffalo Bill Center of the West (Cody), and the Evan's Plunge mineral pool in Hot Springs, SD—a hit with kids. Many rest areas have playgrounds, but facilities in Wyoming may be sparse.

Pet-friendly lodgings are plentiful in national park gateway towns, but note that Yellowstone's boardwalks do not allow pets. Designate a driver to rotate every two hours; the longest stretch without services is between Greybull and Spearfish (90 miles). Plan to stop at the 'Little Bighorn Battlefield' for a sobering history lesson, and beware of deer at dawn and dusk.

• Rest stops: With picnic areas at the Bighorn Canyon and Devils Tower.
• Fatigue: Use the '20-minute rule' and stop at rest areas like the Tongue River Vista.
• Local tips: In Wyoming, radar detectors are prohibited; keep phone mounts handy for speed checks.

Gas stations become sparse east of Idaho Falls, so plan to refuel in larger towns like Salmon, Rexburg, and Buffalo. Diesel is widely available along I-90, but smaller towns may have limited hours. Fuel prices at the start of the route tend to be higher due to remote location; budget around $0.30 per mile for fuel.

The fastest route is I-90 eastbound from Bozeman, but the scenic route via US-20 through Yellowstone adds about 2 hours and requires a park entrance fee, currently $35 per vehicle. If you're driving a large RV, note that some roads in Yellowstone are steep and winding, with a maximum vehicle length of 40 feet. Cell service is patchy west of Billings; download offline maps before leaving.

• Highway numbers: US-93 south to I-84, then I-15 north to I-90.
• Road conditions: Check for mountain passes like Teton Pass (closed in winter) and Powder River Pass (elev. 9,666 ft).
• Fees: Yellowstone NP entrance ($35), Devils Tower NM ($25), Custer State Park ($20).