Lonesome Highway — Centennial Road to Asotin via the Blue Mountains Bench and Grande Ronde Canyon Rim
Canyon rim and coulees above the Grande Ronde confluence.
Most people know the Grande Ronde River where it dumps into the Snake at Troy, Oregon — steelhead country, famous water. Fewer have driven the canyon rim above it from the Washington side, where Forest Road 46 climbs out of the Tucannon drainage through open ponderosa and meadow into the Umatilla National Forest highlands before the road drops back toward the canyon edge near Rattlesnake Grade. The route links Pomeroy on US-12 east through the Blue Mountains on gravel FS roads to the canyon overlooks above the Grande Ronde confluence, then switchbacks down Rattlesnake Grade — a steep, loose-gravel descent that has chewed up passenger cars for generations — and finishes on pavement into Asotin on the Snake River. At the bottom, the Grande Ronde and Snake junction is a legitimate piece of Pacific Northwest wilderness that looks nothing like wheat-belt Washington from 20 miles back.
Difficulty is moderate, with Rattlesnake Grade being the one honest obstacle: narrow, steep, and covered in loose decomposed basalt that washes out every spring. High-clearance 4WD is necessary on the grade; the FS road approach is manageable in a capable AWV with decent tires in dry conditions. Best season is June through October — the grade turns greasy and dangerous when wet. Fuel in Pomeroy or Asotin. No permits required. Cell service is nonexistent through the Blue Mountains segment. Dispersed camping is available on Umatilla NF lands. This is deeply underrated overlanding in a corner of the Pacific Northwest that gets overlooked in favor of the Cascades.
Trail Specs
| Difficulty | Moderate |
|---|---|
| Trail Type | High Clearance, Overland Route |
| Surface | Dirt, Gravel |
| Features | Camping, Remote, Scenic |
| Length (miles) | 72 mi / 115.9 km |
| Duration | 1-2 days |
| Max elevation (ft) | 5200 ft |
| Best season | June-October |
| Minimum vehicle | High-clearance 4WD |
| Nearest town | Asotin, WA |
| Land manager | Umatilla National Forest — Pomeroy Ranger District |
| Permit required | No |
| Cell service | None |
| Water crossings | No |
| Dispersed camping | Yes |
| Official sources | Umatilla National Forest |
| Start coordinates | |
| End coordinates | |
| Copy both for Google Maps directionsClick to copy the directions URL · or open it directly in a new tab | |
| Find on Google | Search on Google → |
Location
Trail Conditions
No recent condition reports. Be the first to post one.
Log in to post a condition report.
Frequently asked questions
Can a stock Tacoma or 4Runner handle this route, or do I need a lifted rig?
A stock high-clearance 4WD like a Tacoma or 4Runner is the minimum — this isn't a trail for a stock crossover or 2WD truck. Lifted rigs aren't required, but decent all-terrain tires and a working low-range will matter on the canyon rim sections and rougher coulees.
When does the route typically open after winter, and is snow a real issue in spring?
June through October is the reliable window. The Blue Mountains bench can hold snow and mud well into May, and early-season clay-heavy dirt roads turn greasy fast — check with the Pomeroy Ranger District before heading out before mid-June.
Do I need a permit to drive or camp on this route?
No permit required to drive the route. Dispersed camping is allowed under Umatilla National Forest rules — no fee, no reservation, standard 14-day stay limit. Stay out of private wheat-farm land along the bench; the boundary isn't always obvious, so pay attention.
What's the hardest section and what should I actually expect there?
The canyon rim descent toward the Grande Ronde confluence is where the route earns its moderate rating — narrow shelf road, loose gravel, and exposure with limited room to recover a mistake. It's not technical rock-crawling, but it demands focus, and passing another vehicle in that stretch would be a problem.
How far is the nearest gas, and is there any water along the route?
Asotin is the logical resupply point at the east end — fill up there or in Pomeroy before heading out west. There's no reliable potable water on the route itself; carry everything you need for 72 miles plus a buffer. Cell service is nonexistent for the full run, so a satellite communicator isn't optional on a 1-2 day remote push like this.
Trail track
No GPX track for this trail yet. If you've driven it and have a track, contribute below.
Log in to contribute a GPX track.