West Yellowstone to Thermopolis: Ultimate Road Trip Guide

Leaving West Yellowstone, Montana (elevation 6,667 ft), the road to Thermopolis, Wyoming begins with a climb over the Continental Divide at Targhee Pass (elevation 7,072 ft) on US-20. This route spans 245 miles and typically takes 4.5 to 5 hours of driving time, not counting stops. The drive transitions from the volcanic plateau of Yellowstone to the stark badlands of the Bighorn Basin, offering a dramatic shift in scenery.

Along the way, you'll encounter geothermal wonders, the headwaters of the Missouri River, and one of the largest hot springs in the world. The route slices through parts of the Greater Yellowstone Ecosystem, a UNESCO World Heritage Site, and offers a blend of natural and cultural attractions that make the journey as rewarding as the destination.

This route includes long stretches of two-lane highway with wildlife crossings; expect deer, elk, and occasionally moose near dawn and dusk. Speed limits are typically 65 mph on US-20, but reduce to 45 mph in construction zones and near the canyon. Winter travel requires chains in mountain passes, and summer thunderstorms can bring hail.

For families, Yellowstone Bear World in Rexburg, Idaho, offers a drive-through wildlife park and a petting zoo, ideal for kids. The Idaho Falls Zoo and the Tautphaus Park are also family-friendly. In Thermopolis, the Hot Springs State Park has a splash pad and picnic areas, and the free state bathhouse is suitable for all ages.

For pets, most rest stops and parks allow leashed dogs; Yellowstone Bear World prohibits pets in the drive-through but has kennels available. Hotels along the route often accept pets, but confirm before booking.

To manage fatigue, take advantage of designated rest areas at Ashton, Idaho (mile 40) and east of Shoshoni, Wyoming (mile 220). For longer breaks, consider the Bear World exit (mile 70) or the Wind River Canyon scenic overlook (mile 200). Plan to stop every 2 hours to stretch; the constant driving through similar landscapes can cause highway hypnosis.

The journey begins in the shadow of Yellowstone's volcanic plateau, where forests of lodgepole pine give way to the potato fields of Idaho's Snake River Plain. The Henrys Fork of the Snake River carves through Mesa Falls, a 114-foot waterfall that is a must-see. Further east, the Tetons rise to the west, providing a backdrop of jagged peaks visible for miles.

As you cross into Wyoming, the landscape transforms into the Wind River Range, a rugged mountain wilderness. The Wind River Canyon, between Shoshoni and Thermopolis, slices through ancient rock layers, offering a geological journey of 2.5 billion years in just a few miles.

Local commerce along the route includes Native American cultural sites in Fort Washakie, the Eastern Shoshone tribal headquarters, and the Wind River Indian Reservation, where visitors can learn about beadwork and traditional crafts. In Thermopolis, the Hot Springs County Museum displays artifacts from the Wyoming Dinosaur Center, promising glimpses of Jurassic-era fossils.

For a taste of local flavor, try a bison burger at a small-town diner or sample huckleberry ice cream, a regional specialty. Farm stands along US-26 offer seasonal produce and local honey.

The primary route (US-20 east to Idaho Falls, then I-15 north to US-26 east) offers reliable highway conditions year-round. An alternate scenic route via Yellowstone National Park's East Entrance and over Sylvan Pass adds 100 miles and 2 hours but includes elevations above 8,500 ft and seasonal closures (typically mid-May to early November).

Fuel stations cluster in West Yellowstone, Ashton, St. Anthony, Rexburg, Idaho Falls, Rigby, Dubois, and Thermopolis. The longest stretch without fuel is about 70 miles between Dubois and Thermopolis, so plan your fill accordingly. Gas prices in the region often run 10-20% higher in tourist towns like West Yellowstone compared to larger cities like Idaho Falls.

• Drive time: 4.5–5 hours without stops.
• Best stops West Yellowstone, MT to Thermopolis, WY include Mesa Falls, Yellowstone Bear World, and the Wind River Canyon.
• For hidden gems, learn how to find the best stops and hidden gems between cities.
• Thermopolis boasts Hot Springs State Park, where the state bathhouse offers free public bathing for visitors.
• Is it worth driving West Yellowstone, MT to Thermopolis, WY? Absolutely, for the geological diversity and the road trip experience.