Rapid City to Butte: Epic SD-MT Road Trip Guide

The journey from Rapid City, South Dakota to Butte, Montana spans roughly 400 miles (643 km) along Interstate 90 West, a route that crosses the Missouri River and climbs into the Rocky Mountains. This drive typically takes 6 to 7 hours without stops, but you'll want to budget at least two days to truly experience the landscapes.

A little-known fact: near the Wyoming border, just off I-90, lies the town of Sundance, Wyoming, where the notorious outlaw Harry Longabaugh (the Sundance Kid) was imprisoned. The route also passes through the historic coal mining town of Gillette, Wyoming, and near the Little Bighorn Battlefield, where General Custer made his last stand.

To maximize your trip, learn how to find the best stops and hidden gems between cities.

I-90 is generally safe, but wildlife crossings (deer, antelope, and occasionally elk) are common, especially at dawn and dusk. The speed limit is 80 mph in South Dakota and Wyoming, 75 in Montana. Use cruise control to avoid speeding tickets.

For families, plan stops every 2-3 hours. The Children's Museum of Northern Wyoming in Sheridan is excellent for kids. In Gillette, the Rockpile Museum teaches about the area's dinosaur and coal mining history.

• Fatigue management: Take a break at the Little Bighorn Battlefield (exit 510) – a somber but educational stop that gets you out of the car. Walk the grounds for 30 minutes.
• Pet-friendly stops: Many rest areas have pet relief areas. In Sheridan, the Red Grade Trail (off I-90) offers a 6-mile hike where dogs are welcome on leash. Pet-friendly lodging includes Best Western Plus in Butte and Motel 6 in Gillette.
• Hidden off-route spots: Just 20 minutes north of I-90 at exit 187 (Wright, WY) is the Thunder Basin National Grassland, a vast shortgrass prairie with virtually no visitors – perfect for an off-grid picnic. Another gem: the ghost town of Cambria, near Newcastle, WY, a former coal mining town abandoned in 1928.

Interstate 90 is the backbone of this trip, a well-maintained four-lane highway. Fuel stops are plentiful in towns like Wall, SD; Gillette, WY; Buffalo, WY; and Sheridan, WY. However, between towns, stretches can exceed 50 miles without services. Always fill up when you see a station.

Gas prices trend lower in Wyoming compared to South Dakota and Montana. As of mid-2025, expect around $3.50/gallon in SD, $3.20 in WY, and $3.60 in MT. A 20-gallon tank will cost roughly $70 to fill.

• Key fuel stops: Wall (exit 109), Gillette (exit 124), Buffalo (exit 299), Sheridan (exit 23), and Hardin, MT (exit 495).
• Rest areas: There are rest areas every 30-40 miles along I-90 with bathrooms and picnic tables.
• Road conditions: In winter, I-90 can close due to snow and high winds, especially between Gillette and Buffalo. Check Montana 511 and Wyoming 511 before departure.

The scenery transitions from the Badlands' eroded spires near Rapid City to the rolling prairie of eastern Wyoming, then to the Bighorn Mountains near Sheridan, and finally to the towering Rockies of Montana. The sheer vastness of the Great Plains offers a stark beauty, with endless skies and distant heat shimmer.

In Butte, the landscape is dominated by the Berkeley Pit, a massive open-pit copper mine that is now a Superfund site and a stark reminder of the region's mining heritage. The pit is over a mile wide and 1,780 feet deep, filled with acidic, heavy-metal-laden water.

• Natural attractions: Theodore Roosevelt National Park (detour south of I-94, but a 3-hour drive from Rapid City, worth a detour), Little Bighorn Battlefield National Monument (near Hardin, MT, just off I-90), and the Bighorn National Forest (scenic drive via US-14 from Sheridan).
• Local commerce: In Butte, visit the World Museum of Mining, the Butte Arts District, and sample the pasties (meat pies) at the famous Pekin Noodle Parlor, the oldest continuously operating Chinese restaurant in the US.