Bunsen Peak Road — Yellowstone Thermal Plateau to Swan Lake Flats
Yellowstone backcountry without the crowds.
Old Bunsen Peak Road peels off the main Yellowstone loop just south of Mammoth Hot Springs and runs 6 miles of unpaved double-track along the base of Bunsen Peak before rejoining pavement near the Gardiner River bridge. Named for Robert Bunsen — yes, the burner guy — the road traces a bench above the Gardner River canyon with direct views into the Mammoth thermal fields. The Sheepeater Cliff basalt columns loom at the north end, and on a quiet morning elk crowd the Swan Lake Flats below. The NPS periodically closes this corridor to private vehicles; check current status before you drive.
When open, it’s high-clearance territory — not technical, but the road surface deteriorates to washboard gravel and embedded rock that will rattle a stock sedan to pieces. A stock 4WD or lifted AWD handles it fine. No permits beyond Yellowstone park entrance fee, no dispersed camping along the road itself. Best window is late June through October before the first hard freeze. Fuel and water at Mammoth, 3 miles north. Cell service is essentially zero. You’re here for the solitude and the geology — this road punches well above its difficulty grade.
Trail Specs
| Difficulty | Moderate |
|---|---|
| Trail Type | High Clearance, Scenic Drive |
| Surface | Gravel, Rock |
| Features | Historic, Remote, Scenic |
| Length (miles) | 6 mi / 9.7 km |
| Duration | Half day |
| Max elevation (ft) | 7400 ft |
| Best season | June-October |
| Minimum vehicle | High-clearance AWD or 4WD |
| Nearest town | Mammoth Hot Springs, WY |
| Land manager | National Park Service — Yellowstone National Park |
| Permit required | Yes |
| Cell service | None |
| Water crossings | No |
| Dispersed camping | No |
| Official sources | nps.gov |
| Start coordinates | |
| End coordinates | |
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| Find on Google | Search on Google → |
Location
Trail Conditions
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Frequently asked questions
Can a stock Tacoma or 4Runner handle Bunsen Peak Road without modifications?
Yes. A stock high-clearance 4WD or AWD rig handles this fine — it's a gravel and rock service road, not a rock crawl. Low-profile cars and minivans will get hung up on the rougher sections near the thermal flats.
When does Bunsen Peak Road actually open each year?
Typically June through October, but Yellowstone's NPS controls access and the exact open date shifts year to year based on snowpack and road condition. Check nps.gov/yell for current road status before you leave — this one can stay gated well into June.
Do you need a special permit to drive Bunsen Peak Road, or does the park entrance fee cover it?
Your standard Yellowstone entrance fee covers access — no separate backcountry vehicle permit required to drive the road itself. That said, if you're camping overnight, you'll need a Yellowstone backcountry camping permit obtained in advance through the NPS.
What's the hardest section of this trail and what should I actually expect?
The roughest stretch is mid-route where loose rock and embedded boulders tighten up the line choices — nothing technical, but it'll rattle unsecured gear and punish low-clearance rigs. At moderate pace it's manageable; the bigger challenge is staying alert for bison and thermal crust near the road edges.
Is there any cell service on Bunsen Peak Road, and how far is the nearest gas from the trailhead?
Zero cell service on this road — plan accordingly and download offline maps before you enter the park. The nearest gas is at Mammoth Hot Springs, roughly 2–3 miles from the north trailhead start, so top off there before you head out.
Trail track
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