Gardiner to Tropic Road Trip: A 705-Mile Guide

The route from Gardiner, Montana to Tropic, Utah is a 705-mile odyssey that begins at the north gate of Yellowstone National Park and ends near Bryce Canyon. Along US-191, I-90, and I-15, you'll traverse three states, cross the Continental Divide, and drop from 5,300 feet to 6,100 feet in elevation.

A unique driving quirk: near the Montana-Idaho border, US-20 becomes a narrow two-lane road through the Targhee National Forest, where moose frequently cross at dawn—a local quirk that demands extra caution.

Road quality is generally excellent: I-15 is a modern interstate, but US-191 north of West Yellowstone is a winding mountain road with frost heaves. Always carry chains from October to April.

• Family-friendly stop: Yellowstone's Grizzly & Wolf Discovery Center in West Yellowstone (open daily, kids go free in winter)
• Pet-friendly: Many rest areas have leash areas; pets are prohibited on boardwalks in Yellowstone but allowed on paved paths.
• Fatigue management: The stretch between Butte, MT and Idaho Falls is long and empty; plan stops every 2 hours at towns like Dillon, MT or Dubois, ID.

Hidden gems off the main route: The Teton Scenic Byway (Idaho 33) from Driggs to Victor offers stunning views of the Tetons, a 40-minute detour. In Utah, the Burr Trail's switchbacks near Boulder are a thrilling gravel alternative to US-12.

Yellowstone's geothermal features dominate the first 50 miles: the Boiling River by Gardiner is a famous hot spring swim spot (check closures). Further south, Idaho Falls' Snake River Greenbelt offers a scenic stroll. Utah's U.S. Route 89 near Tropic winds through the Grand Staircase–Escalante National Monument, a geological sequence of cliffs.

UNESCO World Heritage Sites along or near this route include Yellowstone itself (since 1978) and, if you detour, the Lehman Caves in Great Basin National Park (a designated monument, though not a Heritage site). The only true UNESCO site within 50 miles of the route is Yellowstone.

For local flavor, stop at the Old Idaho Penitentiary in Boise (a 30-mile detour) or the Tropic's Bryce Canyon Pioneer Village, which hosts cowboy poetry readings in summer.

To cover the distance efficiently, you'll spend about 12 hours and 30 minutes of pure driving time. The fastest path is to take US-191 south to Belgrade, then I-90 west to Butte, and finally I-15 south through Idaho into Utah.

• Estimated fuel cost for a 25-mpg car: $125 (based on average $3.50/gal)
• Total elevation gain: 800 feet (net)
• Suggested overnight stop: Idaho Falls, ID (at mile 250) or Pocatello, ID (mile 310)