Idaho Falls to Ketchum Road Trip Guide: Eastern Idaho Highlights

This 140-mile drive on US-20 and US-93 crosses a landscape shaped by the Great Rift volcanic zone—a 600-mile scar. The route climbs from 4,700 feet in Idaho Falls to 5,900 feet in Ketchum. Along the way, you pass the precursor to Yellowstone’s hotspot: Craters of the Moon National Monument.

The drive takes roughly 2 hours and 45 minutes without stops. But to experience best stops Idaho Falls, ID to Ketchum, ID, plan for a full day. When asking how long to drive Idaho Falls, ID to Ketchum, ID, factor in at least 4 hours with stops. The answer to is it worth driving Idaho Falls, ID to Ketchum, ID is a definite yes—this route offers volcanic landscapes, historic towns, and prime recreation.

Fuel is available in Idaho Falls, Blackfoot, Arco, and Ketchum. The empty stretch from Arco to Carey has no services—fuel up in Arco. For a deeper dive on spotting attractions, see how to find the best stops and hidden gems between cities.

Below is a quick overview table.

Road quality is excellent. Hazards include wildlife (deer, elk) at dawn/dusk, especially near Craters of the Moon. Winter requires snow tires or chains in the mountains. No significant construction reported as of 2025.

For family suitability, the route offers many kid-friendly stops: Idaho Falls splash pad, Blackfoot potato museum, Craters of the Moon's easy Trails, and Ketchum's river walk. Pets are welcome at outdoor attractions—keep dogs on leash.

Fatigue management: The straight US-20 can be monotonous. Alternate drivers or take breaks at:

• Rest area at milepost 1 on US-20 (near Blackfoot)
• Craters of the Moon visitor center (restrooms, shade)
• Carey: gas station with cafe

Hidden off-route spots: Explore the lava tube caves at Craters of the Moon (Indian Tunnel, Boy Scout Cave). The ghost town of Gilmore is a 15-mile detour east of Leadore. For a soaking, visit the hot springs at Sunbeam Village (outside Ketchum).

Local culture tip: In Arco, ask about the “Atom City” history—Arco was the first city powered by nuclear energy in 1955. Customize your trip using the linked guide above.

US-20 and US-93 are well-maintained asphalt highways. US-20 is a four-lane divided highway from Idaho Falls to Arco; US-93 from Arco to Shoshone is two-lane with passing lanes.

Speed limits range from 65 to 70 mph. Expect slower speeds in construction zones near Arco. The road is open year-round, but winter may bring snow between Arco and Ketchum.

Fuel stations are spaced roughly 30 miles apart except the 38-mile gap between Arco and Carey. Recommended gas stops:

• Idaho Falls: multiple stations at US-20
• Blackfoot: stations near exit 89
• Arco: two stations on Grand Ave
• Ketchum: stations on Main St

Restrooms exist at these stations, at Craters of the Moon visitor center, and at restaurants in Carey.

Cell service is mostly good on US-20 but spotty on US-93 through Craters of the Moon. Download offline maps in advance. There are no tolls on this route.

Parking is ample at all attractions; Craters of the Moon charges a park entrance fee ($20 per vehicle). Ketchum public lots are free.

From Idaho Falls, the Snake River Plain is flat farmland. Near Blackfoot, you see the Portneuf Range. The landscape transforms after Arco into the volcanic fields of Craters of the Moon—basalt flows, cinder cones, and lava tubes. This area is part of the Great Rift, a National Natural Landmark.

The final stretch from Carey to Ketchum follows the Big Wood River Valley, with sagebrush giving way to pine forests and the Sawtooth Mountains.

Local commerce includes:

• Idaho Falls: farmers market (Sat mornings), local art at Art Museum of Eastern Idaho
• Blackfoot: Idaho Potato Museum (home of the world's largest potato chip)
• Arco: Pickle's Place (historic diner) and the Experimental Breeder Reactor I museum
• Ketchum: Sun Valley Resort, art galleries, outdoor gear shops

UNESCO World Heritage Sites: None directly on route, but Yellowstone National Park (UNESCO site) is a short detour north. Craters of the Moon is a National Monument but not UNESCO.

Climatic conditions vary: July highs reach 90°F in Idaho Falls, 80s in Ketchum. Winter sees snow from November to March. Route aesthetics peak in fall (golden aspen) and spring (wildflowers).