Three Sisters Wilderness Obsidian Mining Circuit
Ancient obsidian quarries in Cascade lava fields
This remote circuit follows Forest Roads 242 and 15 through ancient lava flows to reach the historic obsidian mining district where Native Americans quarried volcanic glass for thousands of years. The route crosses the McKenzie Pass lava fields, navigating sharp basalt boulders and seasonal washouts that challenge even experienced drivers approaching the Three Sisters Wilderness boundary.
Moderate to difficult depending on season and recent volcanic activity repairs. High-clearance 4WD mandatory for sharp lava rock that destroys tires without proper protection. Open June through October when snow clears the pass. Wilderness permits required for hiking beyond trailheads. Fuel in Sisters — this is genuine backcountry with no services for 60 miles. Dispersed camping available at established sites near Proxy Falls. This route combines geological wonder with authentic mining history in one of Oregon’s most volcanic landscapes.
Trail Specs
| Difficulty | Moderate |
|---|---|
| Trail Type | Backcountry, Overland Route |
| Surface | Dirt, Rock |
| Features | Camping, High Altitude, Historic, Remote, Scenic |
| Length (miles) | 34 mi / 54.7 km |
| Duration | 1-2 days |
| Max elevation (ft) | 5325 ft |
| Best season | June-October |
| Minimum vehicle | High-clearance 4WD with tire protection |
| Nearest town | Sisters, Oregon |
| Land manager | Deschutes National Forest |
| Permit required | Yes |
| Cell service | None |
| Water crossings | No |
| Dispersed camping | Yes |
| Official sources | fs.usda.gov |
| 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 without modifications?
Stock high-clearance 4WD is the minimum — a bone-stock Tacoma or 4Runner will manage, but tire protection (skid plates or at minimum sidewall-aware driving) is non-negotiable on this route. Lava rock is brutal on rubber, so run-flats or a solid spare plan are smart. Lifted rigs with all-terrain tires will have more margin on the rockier sections.
When does the trail actually open after winter, and is October pushing it?
June is realistic for a snow-free run — higher sections near the lava fields can hold snow into late May. October is doable but early storms hit the Oregon Cascades fast; check the Deschutes National Forest road conditions before you go. The window is June through early October in a typical year.
Do I need a permit, and is there a fee to drive or camp here?
Yes, a permit is required — the Three Sisters Wilderness has a self-issue permit system for backcountry entry, available at trailheads. As of recent seasons there's no vehicle fee for the Forest Service road access itself, but wilderness regulations apply to any foot travel into designated zones. Verify current requirements at fs.usda.gov/deschutes before your trip since wilderness permit rules in Oregon have been tightening.
What's the hardest section of this route and what makes it technical?
The roughest driving is through the lava field segments where road surfaces turn to loose and sharp volcanic rock — low-traction conditions with high puncture risk, not necessarily extreme obstacles. Clearance isn't the primary concern; it's slow, deliberate tire placement. Plan for reduced speed through these sections, not brute force.
There's zero cell service — how far is the nearest gas and should I carry extra fuel for 34 miles?
Sisters, Oregon is your last stop for fuel, food, and any last-minute gear — fill up there. At 34 miles of backcountry driving on dirt and rock, fuel consumption is higher than highway; carry at least 2-3 gallons of extra fuel if your tank range is tight. You won't find service, a ranger station, or a bailout town until you're back near Sisters.
Trail track
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