Seasonal conditions
April to October — summer heat on the lava is extreme; ride mornings. Verified 2026-11-10.
ROUTE
Craters of the Moon Loop — Arco to Mackay
A ride through two Idahos: 120 km from Arco — the first town powered by nuclear electricity — through the black lava fields of Craters of the Moon to Mackay beneath the Lost River wall.
scenic-road120 km3.7 heasy
<a rel="nofollow" class="external text" href="https://www.flickr.com/people/93062192@N08">Craters of the Moon National M / Wikimedia Commons / Public domain
ABOUT THIS ROUTE
The route in detail
This short loop packs Idaho’s strangest geography: US-20/26/93 from Arco runs the edge of the Great Rift’s lava flows — a frozen black ocean with cinder cones and the walkable Indian Tunnel — then turns up the Big Lost valley to Mackay, where the 12,000-foot wall of the Lost River Range ends the horizon. Arco’s atomic heritage (the town’s BReactors connection and the sail of the USS Nautilus on Main Street) makes the start worth an hour before the ride.
This short loop packs Idaho’s strangest geography: US-20/26/93 from Arco runs the edge of the Great Rift’s lava flows — a frozen black ocean with cinder cones and the walkable Indian Tunnel — then turns up the Big Lost valley to Mackay, where the 12,000-foot wall of the Lost River Range ends the horizon. Arco’s atomic heritage (the town’s BReactors connection and the sail of the USS Nautilus on Main Street) makes the start worth an hour before the ride.
PLAN RESPONSIBLY
Season & safety
Key hazards
- Extreme heat radiating off the black lava in summer.
- Gusts where the lava plain meets the valley.
- Open-range cattle near Mackay.
- Sparse services — Arco and Mackay only.
Required gear
- Certified motorcycle helmet and full protective riding gear.
- Hydration — carry water even on short summer rides.
WAYPOINTS
Route points
- 01
Craters of the Moon visitor center — the lava loop
waypoint
MAP & ROUTE
On the atlas
Elevation1,844 m high point1,616 m low point600 m total climbing10% steepest stretch (km 35)
DESTINATIONS
Places on this route
Craters of the Moon
A volcanic moonscape on the Snake River Plain — cinder cones, lava tubes and wildflower islands where Apollo astronauts trained for the Moon.
South Central Idaho
Twin Falls & the Snake River Canyon
The Magic Valley capital on the Snake: Shoshone Falls’ 212-foot curtain, BASE jumpers off the Perrine Bridge, and the canyon Evel Knievel tried to jump.
South Central Idaho
INTERESTS
Why riders & travellers love it
WEATHER
Weather along the route
Forecast data from Open-Meteo. Updated regularly.
REGIONS
Explore the region
KEEP EXPLORING
The atlas continues
More routes, destinations and stories from every corner of the world — start where you like below.