West Yellowstone to Spearfish: Ultimate Road Trip Guide

The route from West Yellowstone, Montana to Spearfish, South Dakota crosses the Continental Divide three times, tracing the ancient Absaroka volcanic field and the southern edge of the Montana Glaciated Plains. The drive covers roughly 420 miles via US-20 East, I-90 East, and US-14 East, passing through the towns of Dubois, Cody, Greybull, and Buffalo before dipping into Wyoming’s Bighorn Basin.

One quirky fact: near Buffalo, Wyoming, the highway tunnels under the Powder River Pass at 9,666 feet, making it one of the highest paved passes in the Northern Rockies accessible year-round. This road has been a favored migration corridor for pronghorn antelope for millennia, and today, wildlife crossings are common.

For anyone asking how long to drive West Yellowstone, MT to Spearfish, SD, the answer is around 7 to 8 hours of pure driving time, not including stops. The route offers a dramatic transition from volcanic geothermal basins to the high desert badlands.

West Yellowstone sits at the doorstep of Yellowstone National Park, a UNESCO World Heritage Site. The park’s geothermal features, including Old Faithful, are a major draw, but the drive itself showcases the Absaroka Mountains, the Bighorn Basin’s fossil-rich cliffs, and, near Spearfish, the Black Hills’ granite spires.

UNESCO recognition extends to Yellowstone, but the route also passes near the Cave Junction in South Dakota, not far from Jewel Cave National Monument, a separate must-see.

Local commerce along the route thrives on tourism and agriculture. In Cody, the Irma Hotel (est. 1902) offers a historic dining experience with buffalo burgers. In Buffalo, the Occidental Hotel (est. 1880) serves regional beef and craft beer. For a quick bite, gas station delis in towns like Greybull offer house-made pasties, a nod to Cornish miners.

For those planning stops, how to find the best stops and hidden gems between cities is a helpful resource.

Road quality is high, but wildlife crossings (elk, deer, bighorn sheep) are frequent, especially at dawn and dusk. Use high beams when safe, and scan the shoulders. The route includes several steep grades, so use low gears to avoid brake overheating.

For families, the route is highly suitable: Yellowstone’s Grizzly & Wolf Discovery Center in West Yellowstone offers kid-friendly exhibits, and the Museum of the Bighorn Basin in Greybull features hands-on fossil exhibits. Playgrounds are available in most town parks.

Pet-friendly framework is solid: most motels in Cody and Buffalo accept dogs, and there are numerous rest areas with leash-friendly green spaces. Ensure pets are restrained while driving.

Fatigue management: plan rest stops every two hours. Recommended rest zones include rest areas near Greybull and the Powder River Pass, plus larger service centers in Buffalo and Gillette. Coffee and energy drinks are available at convenience stores, but hydration is key at high elevations.

Fuel stations cluster around Cody and Greybull, WY, but stretch between these towns can be 60+ miles with no services. Plan fuel stops accordingly, and note that gas prices tend to be lower in Montana than in Wyoming, especially near the national park gates.

• Interstate 90 is a well-maintained four-lane freeway from Buffalo to Spearfish.
• US-14 East from Greybull to Buffalo is a two-lane highway with passing lanes on grades.
• Expect occasional construction delays during summer months on I-90.

The toll-free route offers excellent value; total fuel costs typically range $45–$60 for a standard sedan. Lodging prices jump near Spearfish due to tourist demand, but smaller towns like Buffalo offer budget motels around $80–$120 per night.

Road conditions are generally good from May through October, but winter travel may require chains on passes.