Green River to Choteau: Epic Utah-Montana Road Trip

The route from Green River, UT to Choteau, MT spans 725 miles via I-15 and I-90, crossing three states and five distinct ecosystems. Your tires will roll over the Continental Divide at Monida Pass (6,870 ft), a historic railroad gateway.

Start early: the first leg between Green River and Salt Lake City sees heavy truck traffic on I-80, so plan for a 2-hour cushion. The entire drive without stops takes 11 hours, but you'll want at least two days.

Just north of Arco, ID, Craters of the Moon National Monument sprawls across 750,000 acres of volcanic basalt – a lunar-like landscape shaped by eruptions 2,000 years ago. The park's loop road is a 7-mile detour, but add 45 minutes for a quick hike.

Continuing north, the Beaverhead Mountains rise over the Montana border, their granite peaks forming the backdrop for the historic town of Dillon, named after a railroad surveyor.

Local commerce thrives in small towns like Spencer, ID, where a combination gas station and diner serves huckleberry milkshakes. In Choteau, the Old Trail Museum showcases dinosaur fossils found on nearby Egg Mountain – including Maiasaura, Montana's state fossil.

For a taste of local culture, stop at the Choteau Farmers Market on Saturdays (July-September) for Montana-made crafts and produce.

Fuel economy matters: gas stations become sparse north of Idaho Falls, especially on US-287. Expect prices 15% higher in rural Montana.

Cell service vanishes for 70 miles across Craters of the Moon, so download offline maps.

Truck stops like Love's and Flying J cluster near Ogden, UT and Butte, MT – use them for clean restrooms and hot coffee.

• I-15/I-90 are four-lane divided highways, while US-287 is a two-lane road with occasional passing lanes.
• Road construction common near Utah's Spanish Fork Canyon – check UDOT before departure.
• Montana's speed limit on interstates is 80 mph, but reduces to 65 mph on US-287 and through towns.

Road quality varies: Utah maintains smooth asphalt, but Montana's secondary routes crack from freeze-thaw cycles. Watch for deer and elk at dawn and dusk, especially between Lima and Choteau.

For kids, the Idaho Falls Zoo (Tautphaus Park) offers a 2-hour break, and the Museum of Clean in Pocatello has interactive exhibits. Pets need a break too: rest areas like the one at Beaver Canyon (mile marker 1 on I-15) feature watering stations and shade.

Fatigue crashes are common on long stretches. Pull over every 2 hours – the Arco rest area has picnic tables, and the rest stop at Monida Pass has stunning views to clear your mind.

Hidden gems off the route: the abandoned town of Gilmore, ID (take exit 143) offers ghost-town exploration, and the Earthquake Lake visitor center near Hebgen Lake explains the 1959 quake that formed Quake Lake.