Thermopolis to Gillette: A Wyoming Road Trip Guide

The drive from Thermopolis to Gillette covers about 210 miles (338 km) of some of Wyoming's most dramatic and geologically significant terrain. You'll traverse the southern edge of the Bighorn Basin, cross the Bighorn Mountains at Powder River Pass (elevation 9,666 feet), and descend into the high plains of northeastern Wyoming. This route is a journey through time, where ancient sea beds, volcanic ash, and glacial valleys tell a story that predates the dinosaurs.

The drive typically takes around 3.5 to 4 hours without stops, but the journey offers so much that lingering is highly recommended. From hot springs to fossil buttes, and from historic ranches to modern energy towns, this road trip is a microcosm of Wyoming's diverse character. Before you set out, check the weather: the pass can be snowy as early as October and as late as May.

The route showcases three distinct landscapes: the red desert of the Bighorn Basin, the alpine forests of the Bighorn Mountains, and the rolling prairie of the Powder River Basin. Each zone offers its own attractions and local flavor.

Thermopolis is home to the world's largest mineral hot spring, with water flowing at 127°F (53°C). The State Bath House offers free admission to the mineral pools, a perfect start to your journey. Just east of town, the Wyoming Dinosaur Center displays real fossils from the nearby Morrison Formation, including a 100-foot-long Diplodocus cast.

Worland, the next stop, is a farming community known for its sugar beet processing. The Washakie Museum & Cultural Center tells the story of the region's Native American history and the early pioneers. If you're hungry, try a local diner for breakfast burritos or a steak sandwich.

As you climb into the Bighorn National Forest, the landscape transforms into pine forests and wildflower meadows. Ten Sleep, a small town at the base of the mountain, offers a glimpse into Wyoming's ranching heritage. The Ten Sleep Brewing Company, though small, serves excellent craft beer and homemade pizza—a great place to stretch your legs.

Crossing the Bighorn Mountains, you'll pass fields of granite boulders and glacial lakes. The summit, Powder River Pass, is a popular spot for a photo op. Descending into Buffalo, the landscape opens up to the plains, and you'll see the historic Occidental Hotel, a landmark that has hosted celebrities and cowboys since 1880. Nearby, the town of Kaycee is the gateway to the Hole-in-the-Wall country, made famous by outlaws like Butch Cassidy.

The main highways are U.S. 20/26 from Thermopolis to Worland, then U.S. 16 over the Bighorn Mountains to Buffalo, and finally Interstate 90 east to Gillette. The road is well-maintained, with the mountain section featuring sweeping curves and limited visibility in fog. Expect cell service to be spotty in the mountains; plan accordingly.

• Fuel: Gas stations are plentiful in Thermopolis, Worland, Ten Sleep, and Buffalo, but sparse over the pass and along I-90. Fill up before leaving Worland or Buffalo.
• Restrooms: Public restrooms are available at rest areas in Buffalo and near Gillette, plus at most fuel stops.
• Towing: AAA coverage is recommended because the pass is remote, and response times can be long.

If you're wondering whether it's worth driving from Thermopolis to Gillette, the answer is a resounding yes—the contrasts in scenery are unmatched. The best way to find hidden gems is to plan ahead and take a few detours off the main road.

Safety on this route is paramount. The mountain pass has grades up to 6% and can be icy in winter. Always carry chains in cold months and be aware of wildlife, especially deer and elk at dawn and dusk. The speed limit drops in construction zones, so obey signs for your safety.

• Family-friendly stops: The Wyoming Dinosaur Center in Thermopolis offers hands-on dig experiences for kids. The Bighorn National Forest has numerous picnic areas and short trails, such as the hike to Lake Helen near Ten Sleep. In Buffalo, the Jim Gatchell Memorial Museum has weapons and artifacts that fascinate older children.
• Pet-friendly considerations: Many outdoor parks and trails allow leashed pets. The Bighorn National Forest is largely open to dogs, but keep them under control to avoid conflicts with wildlife. Rest areas along I-90 have pet-walking areas.
• Food on the go: Fast food chains are available in Thermopolis, Worland, Buffalo, and Gillette. For faster service, pack a cooler with drinks and snacks; rest stops have vending machines but limited fresh options.
• Fatigue management: There are several designated rest areas along I-90, especially between Buffalo and Gillette. Also, the town of Wright, about halfway between Buffalo and Gillette, has a convenience store and an ATM—a safe place to take a break. Plan to switch drivers every two hours if possible.