West Yellowstone to Pocatello: Scenic Drive Guide

The route from West Yellowstone, MT to Pocatello, ID follows US-20 and I-15 for roughly 160 miles, passing through the Henrys Fork Caldera, a volcanic feature that shaped the landscape you'll traverse. Along the way, you cross the Continental Divide at an elevation of 7,092 feet near Targhee Pass, a milestone that marks the boundary between Atlantic and Pacific watersheds.

This drive, typically taking 2.5 to 3 hours without stops, offers a compact cross-section of the Northern Rockies, from geyser basins to high desert. It's a journey where the scenery shifts every few miles, rewarding drivers who take time to pull over and look.

Speed limits vary: 65 mph on US-20 east of Ashton, 70 mph on US-20 between Ashton and Idaho Falls, and 80 mph on I-15. Ranch animals, especially deer and elk, are a hazard around dawn and dusk, with more than 1,000 vehicle-animal collisions reported annually in eastern Idaho.

Rest areas are available at the Ashton St. Anthony Sandhills exit and the Fort Hall Rest Area near Blackfoot, both with restrooms and vending machines. For a longer break, a detour to the exotic animals of the Yellowstone Bear World (near Rexburg) is popular with families, as is the historic train depot in Pocatello, now home to a railroad museum.

For pet owners, most roadside stops, including rest areas and parks, have designated pet areas; remember to carry water and waste bags. To keep your dog cool in summer, pour water on their paws.

Plan rest breaks every two hours; the route has many pullouts and small parks. For discovering more such stops, see how to find the best stops and hidden gems between cities. To manage fatigue, pair driving with a quick walk around a rest area.

As you leave West Yellowstone, you pass through the Madison River valley, where the river tumbles over volcanic basalt. At Mesa Falls Scenic Byway (off US-20 near Ashton), two waterfalls—Upper and Lower Mesa Falls—plunge over cliffs formed by ancient lava flows. The byway includes a 2-mile round-trip hike to a viewpoint that faces the falls.

The region's volcanic soils support extensive potato farming, particularly around Blackfoot, which calls itself the 'Potato Capital of the World.' Local grocery stores and roadside stands often sell fresh produce in season. The area also has a Mormon pioneer heritage, visible in the tidy farmsteads and the LDS temple in Idaho Falls, which overlooks the Snake River.

Across the entire route, casual diners and cafes in small towns serve hearty American fare, but the most memorable meals feature local trout from the Snake River.

The highways are well-maintained, with US-20 a two-lane road through ranchland and I-15 a four-lane divided freeway south of Idaho Falls. Winter driving can be treacherous due to snow and ice, especially over the pass, but summer brings clear roads and 17 hours of daylight.

• Fuel stops: Ashton, St. Anthony, Idaho Falls, Blackfoot (roughly every 20-30 miles).
• Current gas prices in the region hover around $3.20 per gallon, slightly below national average, reflecting Idaho's lower fuel taxes.
• Given an average fuel economy of 25 mpg, the round trip from West Yellowstone to Pocatello and back could cost about $40.
• Given the proximity to Yellowstone, expect higher prices for goods and services within 30 miles of the park boundary.