Hill City SD to Dillon MT: Black Hills to Big Sky Road Trip

Leaving Hill City, South Dakota, you crest the eastern edge of the Black Hills, a dome of ancient granite that pushed up 60 million years ago. The route west to Dillon, Montana, spans roughly 630 miles, crossing the Missouri River, the badlands of Wyoming, and the Bighorn Mountains before descending into the Beaverhead Valley.

One immediate quirk: while Hill City sits at 5,100 feet, the road drops to 2,900 feet near Buffalo, Wyoming, then climbs to 8,000 at Powder River Pass. That rollercoaster is just the start of what makes this drive compelling.

Here's how to plan it, what to expect, and where to pause for the best stops Hill City, SD to Dillon, MT.

In total, how long to drive Hill City, SD to Dillon, MT is just under 11 hours, but with overnight stops and sightseeing, plan for 2–3 days. The question is it worth driving Hill City, SD to Dillon, MT depends on your appetite for wide-open skies and roadside history.

Long stretches of straight highway can lull drivers into drowsiness. To combat fatigue, plan a break every 2 hours or 150 miles. Designated rest areas exist near Moorcroft, WY; Sheridan, WY; and Billings, MT. These have picnic tables and restrooms, but no vending machines—pack water.

For families, a must-see is the Wyoming Dinosaur Center in Thermopolis (a 90-minute detour). Kids can watch paleontologists prep fossils. If you want a quick leg stretch, the Spanish Point Historical Marker near Greybull offers a short interpretive trail.

Pet-friendly options include the Big Sky Dog Park in Bozeman (just off I-90) and numerous trailheads on the Bighorn National Forest where dogs are allowed on leash. Always carry water and a bowl, as Wyoming summers are dry and hot.

Road safety: I-90 is federally funded, so it's well-marked and barrier-guarded. However, between Hardin and Billings, Montana, there are occasional livestock on the highway. In winter, carry chains and ablanket.

Hidden off-route spots: Secluded camping near the Tongue River Canyon, or the ghost town of Kirwin in the Absaroka Mountains (requires high-clearance vehicle). These are best to visit with a local guide.

The most direct route is US-16 west to I-25 north, then I-90 west through Montana. This traverses some of the most remote stretches in the lower 48—between Buffalo and Sheridan, you'll drive 60 miles without services, so plan fuel and snacks.

• Fuel prices: As of 2025, average gas cost is around $3.50/gal. For a 15-gallon tank, budget $52 per fill-up; you'll need ~3 fill-ups for the whole trip.
• Weather: Wyoming winds can exceed 40 mph, especially between Kaycee and Buffalo. Check wind advisories before departing.
• Road quality: I-90 is well-maintained, but deer and antelope frequent the roadside at dawn and dusk.

In winter, sections of I-90 near the Wyoming/Montana border close for snow. Even in summer, afternoon thunderstorms can cause sudden downpours. Unlike other routes, this one has no tolls, but you'll pass through several small towns where speed limits drop abruptly—like Buffalo (25 mph in school zones) and Sheridan (30 mph downtown).

For a deeper dive on spotting unique roadside attractions, see how to find the best stops and hidden gems between cities.

West of Hill City, you pass through the Red Valley, where the sandstone creates a crimson hue. Further along, the first major landmark is Devils Tower National Monument (detour 30 miles north of US-14). It's a sacred site for six Native American tribes and the first declared US National Monument in 1906. If you're short on time, the nearby town of Hulett offers a fuel station and a diner.

In Buffalo, Wyoming, stop at the Occidental Hotel, which has hosted Buffalo Bill Cody and Teddy Roosevelt. The hotel's bar serves excellent elk burgers.

The Bighorn Mountains, crossed via US-14 (Bighorn Scenic Byway), are a 9,000-foot-high meadowland. The road is closed from November to May—check conditions. At the summit, you'll find the Medicine Wheel, a 700-year-old Native American stone structure.

As you drop into Sheridan, Wyoming, the culinary scene reflects a mix of cowboy and New West influences. The Cowboy Cafe serves homemade pies, but beware: portions are large. For a quick meal, try the local favorite, the mint shake at Crest View Drive-In.

Further west, the Clark Fork River canyon offers rafting in July and August. Local commerce thrives on tourism, with shops selling Western gear and souvenirs.