Lonesome Highway — Centennial Range Divide to Macks Inn via Targhee Plateau Back Road
The only east-west range in the lower 48 — mostly ignored.
This route runs from the Red Rock Pass area along the spine of the Centennial Range — the only east-west mountain range in the lower 48 — dropping south through the Caribou-Targhee National Forest onto the volcanic flats of the Targhee Plateau before reaching Macks Inn on the Henry’s Fork of the Snake River. The gravel and dirt road follows Forest Road corridors across open sage and lodgepole country with sweeping views into the Island Park caldera to the south and the Montana border highlands to the north. Moose, pronghorn, and sandhill cranes are common at the lower elevations. Wildlife pressure here is real — this is grizzly country on the Targhee side.
The road demands a high-clearance 4WD in spring and after summer storms, when the clay sections become genuinely slick and soft. Most of the route is passable in a capable stock rig mid-summer through September. No permits required on the Forest Service sections, and dispersed camping is available throughout the Targhee corridor. Fuel at Macks Inn or West Yellowstone — plan accordingly. Cell service is essentially zero from Red Rock Pass to the Henry’s Fork. What this route delivers is the rare combination of Continental Divide solitude, volcanic plateau drama, and Henry’s Fork meadow beauty — all in one long, unhurried day.
Trail Specs
| Difficulty | Moderate |
|---|---|
| Trail Type | Backcountry, High Clearance, Overland Route |
| Surface | Dirt, Gravel, Mixed |
| Features | Camping, Historic, Remote, Scenic |
| Length (miles) | 58 mi / 93.3 km |
| Duration | 1-2 days |
| Max elevation (ft) | 7120 ft |
| Best season | July-September |
| Minimum vehicle | High-clearance 4WD |
| Nearest town | Macks Inn, ID |
| Land manager | Caribou-Targhee National Forest — Island Park Ranger District |
| Permit required | No |
| Cell service | None |
| Water crossings | No |
| Dispersed camping | Yes |
| Official sources | Caribou-Targhee NF Island Park Ranger District |
| Start coordinates | |
| End coordinates | |
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Location
Trail Conditions
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Frequently asked questions
Can a stock Tacoma or 4Runner handle this trail, or do I need a lifted rig?
A stock high-clearance 4WD like a Tacoma, 4Runner, or Wrangler is the stated minimum and is genuinely sufficient for normal conditions. Lockers and a lift aren't required, but airing down and low-range will earn their keep on the rougher sections near the Centennial Divide.
When does this route actually open after winter, and is snow a real risk in July?
The plateau sits above 7,000 feet and the Centennial Range holds snow late — realistically mid-July before the route is reliably passable, sometimes later after heavy winters. Shoulder season runs push into October, but early fall snowstorms can close it fast with little warning. Check with the Island Park Ranger District before you go.
Do I need a permit to drive this route or camp along it?
No permit is required to drive the route. Dispersed camping is allowed on Caribou-Targhee National Forest land without a fee or reservation — standard Leave No Trace rules apply, and you must stay outside any posted restricted zones. No campfire permits are currently required for this area, but check current fire restrictions before your trip.
What's the hardest section of this route and what should I actually expect?
The roughest terrain is concentrated near the Centennial Divide crossing on the Montana-Idaho border — expect loose rock, uneven two-track, and some rutting from wet-season traffic. Nothing on this route is technically gnarly, but it's remote enough that a mechanical problem or getting stuck is a real problem, not an inconvenience, since self-recovery is on you.
How far is it to the nearest gas from the trailhead, and is there water along the route?
Macks Inn has a gas station and is the closest fuel stop near the east end of the route; top off there and carry extra if you're starting from the Centennial Divide end near the Montana border. There's no reliable treated water on the plateau, so bring everything you need — any surface water should be filtered before drinking.
Trail track
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