Road Trip Lava Hot Springs ID to Spearfish SD: Guide

This route follows U.S. Highway 20 east through Idaho, then I-15 north to I-90 across Wyoming and South Dakota. It's the most direct path, covering 634 miles (1,020 kilometers). Notably, at mile 42 west of Spearfish, you cross the Continental Divide at an elevation of 6,817 feet—a subtle crest that marks the watershed separation.

This is not a scenic interstate corridor; it's a working highway linking ranching towns and energy fields. The drive passes through the edge of Yellowstone's volcanic plateau, then into the high plains, and finally descends into the Black Hills. You'll see signposts for places like Buffalo, Wyoming, a town of 4,588 people that services westbound travelers.

The journey takes about 9 hours and 45 minutes of driving time, excluding stops. Winter weather can close sections between April and October, so always check road conditions. For planning flexibility, here are key distances and times.

Winter driving on this route requires tire chains and survival gear. Wind gusts on I-90 can exceed 50 mph, causing snow drifts. Year-round, wildlife such as elk and pronghorn are active at dawn and dusk, especially between Buffalo and Sundance.

For families, the drive includes kid-friendly attractions like the Idaho Falls Zoo (small but manageable). In Buffalo, the Jim Gatchell Memorial Museum offers pioneer exhibits. Spearfish has a fish hatchery that is popular with children.

Pets are welcome at most rest areas, but only a few hotels along the route are pet-friendly. Best to book in advance. The Spearfish KOA, for example, has pet stations and fenced dog runs.

To manage fatigue, the highway has mile-marker signs every ten miles. Every 2 hours, pull into a rest area or truck stop for a 15-minute break. Plan to stop at the Devils Tower view turnout (mile 520) for a short walk.

For deeper insights into planning this trip, see this guide on how to find the best stops and hidden gems between cities.

• Best stops Lava Hot Springs, ID to Spearfish, SD include: Idaho Falls, Buffalo, and Devils Tower.
• How long to drive Lava Hot Springs, ID to Spearfish, SD? About 9 hours 45 minutes.
• Is it worth driving Lava Hot Springs, ID to Spearfish, SD? Yes, for the Black Hills and wildlife.
• Things to do between Lava Hot Springs, ID and Spearfish, SD: visit the Buffalo Bill Center, hike at Devil's Tower, geothermal pools.

This route touches the northern edge of the Greater Yellowstone Ecosystem, visible in the foothills around Idaho Falls. As you cross into Wyoming, the Bighorn Mountains rise to 13,000 feet, offering a backdrop for the drive. The landscape transitions from sagebrush steppe to rolling prairies, then to ponderosa pine forests entering South Dakota.

Local commerce centers on agriculture and mining. In Buffalo, Wyoming, the historic Occidental Hotel (built 1880) is a stopping point for travelers. Small towns like Basin, Wyoming, have diners serving regional specialties like chicken-fried steak. For a local brewery, Black Tooth Brewing in Sheridan (near Buffalo) offers tours.

The area has one UNESCO World Heritage Site within 20 miles of the route: the Yellowstone-Grand Teton World Heritage Site (designated 1978), though you won't see its geysers from the highway. To access it, you'd detour 200 miles west.

For hidden gems, consider the Powder River Basin mineral belt, where you can see dinosaur quarries. At Rock Creek, Montana (a short detour north), you'll find a restored stagecoach station. This is off-the-beaten-path territory, far from tourist crowds.

Fuel costs average $54 for a mid-size sedan at current national prices. Gas stations cluster at Idaho Falls (mile 70), Buffalo (mile 450), and Gillette (mile 520). Plan to refuel every 200 miles as rural stretches have limited services. The last station before Spearfish is at Sundance, Wyoming.

Road quality is generally good, with 75% interstate sections. Two-lane stretches of US-20 east of Idaho Falls have lower speed limits and occasional livestock crossings. Cell phone coverage drops to 2G on parts of US-20 and US-16 in Wyoming. A paper map or offline GPS is recommended.

• Interstate rest areas every 60-80 miles provide picnic tables and restrooms.
• US-20 through Idaho is a designated scenic byway, but keep expectations realistic: it's pastoral, not dramatic.
• In winter, I-90 in Wyoming has chain-up areas and high wind warnings.