West Yellowstone to Richfield: Mountain Route Guide

The route from West Yellowstone, MT (elevation 6,667 ft) to Richfield, UT (5,354 ft) spans roughly 300 miles along US-20, I-15, and US-50, crossing the Continental Divide twice. This drive offers a dramatic transition from volcanic plateaus to high desert, with a rich history of Native American tribes, fur trappers, and Mormon pioneers.

Notably, the route passes through the site of the 1959 Hebgen Lake earthquake, which formed Quake Lake and reshaped the Madison River canyon. The drive typically takes 5 to 6 hours without stops, but explores of natural wonders will easily extend it to a full day.

Beyond the geysers of Yellowstone, the route unveils the otherworldly Craters of the Moon National Monument & Preserve (a short detour via US-20/US-26), a volcanic landscape of lava fields and cinder cones. Near Idaho Falls, the bone-dry lava beds give way to lush farmland along the Snake River, a stark contrast that defines the region's beauty.

The drive also parallels the historic Oregon Trail near Fort Hall, with interpretive sites like the Idaho Museum of Natural History in Pocatello offering insights into frontier life.

Local commerce thrives in small towns: in Ashton, ID, stop at a roadside stand for fresh huckleberries; in Blackfoot, ID (the 'Potato Capital of the World'), visit the Idaho Potato Museum. These pit stops support local economies and provide authentic souvenirs.

For a deeper dive into finding hidden gems, refer to how to find the best stops and hidden gems between cities. This guide emphasizes the value of exploring beyond the main highway.

Safety on this route hinges on weather awareness and wildlife vigilance. Deer and elk are common near dawn and dusk, especially in the national forests. Carry bear spray if hiking near Yellowstone's borders, and always adhere to speed limits on winding mountain passes.

For families, consider a stop at the Yellowstone Giant Screen Theatre in West Yellowstone for an educational start. Kids will enjoy the lava tubes at Craters of the Moon, but ensure flashlights and sturdy shoes.

Pet-friendly facilities exist at most rest areas, but leash laws are strict in national forests. Pack a portable water bowl and refuse bags; in summer, asphalt can burn paws, so use designated grassy areas.

To combat fatigue, plan rest stops at the Idaho Falls Greenbelt or the Pocatello Zoo—both offer easy access and amenities. On US-50, the Fishlake Scenic Byway has several pullouts with picnic tables, perfect for a stretch.

Fuel stations are plentiful along I-15 in Idaho Falls, Pocatello, and Utah, but sparse on US-20 and US-50—fill up before leaving West Yellowstone. Gas prices tend to be lower in Idaho than in Montana or Utah, so plan refueling accordingly.

The road quality is excellent on Interstates, but US-20 through Targhee National Forest and US-50 through the Fishlake National Forest are winding and require attention, especially in winter. Cell service is intermittent in remote stretches; download offline maps.

• US-20 from West Yellowstone to Idaho Falls offers scenic mountain views but is two-lane mostly.
• I-15 from Idaho Falls to Pocatello is a modern freeway with rest areas every 30 miles.
• US-50 from I-15 to Richfield is a scenic byway with few services—carry extra water.
• Winter travel requires snow tires and chains; check road conditions via 511 or local apps.