Idaho Falls to Green River: Epic Wyoming Road Trip Guide

From Idaho Falls at 4,705 feet to Green River's 6,155 feet, this 249-mile route climbs steadily through volcanic plains, mountain passes, and high desert. The drive on US-20 and I-80 takes about 4 hours without stops, but the best stops Idaho Falls, ID to Green River, WY demand at least a full day.

Geologically, this route crosses the eastern Snake River Plain, a massive volcanic province shaped by the Yellowstone hotspot. The lava flows near Arco and Craters of the Moon are visible reminders of eruptions that ended just 2,000 years ago. The highway itself follows portions of the historic Oregon Trail, with ruts still visible in some areas.

How long to drive Idaho Falls, ID to Green River, WY? Nonstop it's 3 hours 50 minutes, but plan for 6-8 hours to explore. The question is it worth driving Idaho Falls, ID to Green River, WY is answered by the surreal landscapes, unique geology, and small-town charm along the way. For a deeper dive into trip planning, check out this guide on how to find the best stops and hidden gems between cities.

The dominant landscape is the Snake River Plain, a flat volcanic expanse that gives way to the Caribou-Targhee National Forest near the Wyoming border. Craters of the Moon National Monument is the geological centerpiece, with lava flows, cinder cones, and caves. The park's visitor center has exhibits on volcanic activity and the area's unique ecology.

Further east, the Bear River Range offers mountains and valleys. At Soda Springs, you can see the Soda Springs Geyser, a man-made geyser that erupts every hour. The area is also known for its travertine formations, which have been mined for decorative stone.

Local commerce along the route includes small towns like Arco (home to the first nuclear reactor to power a city, the Experimental Breeder Reactor I), and Montpelier (known as the 'Oregon Trail Oasis'). In Soda Springs, the historic county courthouse and the Soda Springs Museum offer cultural insights. For things to do between Idaho Falls, ID and Green River, WY, you can visit the Bear Lake Scenic Overlook just before the Wyoming border.

• Arco: Atomic City, EBR-1 National Historic Landmark
• Craters of the Moon: Wilderness hikes, lava tube caves
• Soda Springs: Geyser, Sheep Rock, Oregon Trail History
• Green River: Sweetwater County Museum, Killpecker Sand Dunes

Fuel stations are plentiful in Idaho Falls, Arco, Pocatello, and Montpelier, but sparse between Soda Springs and the Wyoming border. Always fill up before leaving Idaho Falls or Arco. Diesel and regular unleaded are available everywhere; premium fuel may be limited at smaller stations.

• Idaho Falls: multiple stations near US-20 exit
• Arco: one Chevron and a Sinclair, both open 6am-10pm
• Pocatello: ample options near I-15
• Soda Springs: two stations, one with 24-hour pumps
• Green River: several stations on I-80

The route is fully paved with US-20 being a two-lane highway and I-80 a four-lane interstate. The road quality is good, but watch for wildlife especially dawn/dusk. The speed limit on US-20 is 70 mph, on I-80 80 mph.

Cell phone coverage is intermittent on US-20 between Idaho Falls and Arco, and near Craters of the Moon. Once on I-80, coverage is reliable. Download offline maps for the remote sections. There are no tolls on this route.

• Key junction: US-20/US-26 junction at Idaho Falls
• Key junction: US-20/US-93 at Arco
• Key junction: I-15 at Blackfoot (detour to Pocatello)
• Key junction: US-30 at Soda Springs

The route has long stretches with minimal services. Always carry water, snacks, and emergency supplies. Winter conditions from October to April can bring snow and ice, especially on US-20 near Craters of the Moon. Check weather before departure. Summer temps exceed 90°F, so hydrate frequently.

Rest stops: Idaho Falls Rest Area (mile 0), Arco Rest Area (mile 77), Craters of the Moon Rest Area (mile 95), Little America Rest Area (Wyoming, mile 220). Official rest areas have restrooms and picnic tables. Fatigue management: stop every 2 hours, swap drivers if possible.

Family suitability: Craters of the Moon is excellent for kids – easy trails, visitor center, and junior ranger program. The lava tube caves are fun but require flashlights. Soda Springs Geyser is also kid-friendly. Pet-friendly: Pets are allowed at Craters of the Moon but must be leashed. Most motels in Arco and Green River accept pets.

• Best family stop: Craters of the Moon National Monument
• Best pet stop: Craters of the Moon (leashed), rest areas
• Best fatigue break: Little America Rest Area (clean, with coffee)

Hidden off-route spot: The City of Rocks National Reserve near Almo, Idaho, about 40 miles south of the main route on I-84. It's a climber's paradise with striking granite spires. Also, the Massacre Rocks State Park just west of Pocatello offers pioneer history and camping.