Crowley Lake Road to Benton Crossing — Long Valley Caldera Desert Basin Traverse
Volcanic basin drive most Mammoth visitors never find.
Long Valley Caldera is one of the largest supervolcano calderas in North America — 20 miles wide, still thermally active, and largely bypassed by the US-395 crowd racing to Mammoth. The dirt roads crossing the caldera floor between Crowley Lake and Benton Crossing cut through a strange, open basin ringed by the Glass Mountains to the east and the Sierra Nevada to the west. Hot Creek Geologic Site sits mid-route, where boiling vents erupt from the creek bottom and the steam rises year-round. The road continues east past the Owens River fishing access tracks and the tufa formations along the lake’s north shore before reaching the Benton Crossing bridge, where fly fishers park trucks and the road reconnects to pavement.
This is firmly in the easy-to-moderate range — mostly graded dirt and gravel, some soft volcanic pumice in sections that’ll swallow a street tire sidewall if you’re not paying attention. High clearance preferred but a capable all-wheel drive handles it in dry conditions. Best driven spring through fall; the caldera floor sits around 7,000 feet and gets snow. No permits needed. Cell service is spotty near Hot Creek, non-existent across the eastern basin. Mammoth Lakes is your fuel and supply stop; the loop itself takes a half-day but the fishing access roads off Benton Crossing can eat a full day if you let them.
Trail Specs
| Difficulty | Easy |
|---|---|
| Trail Type | High Clearance, Overland Route, Scenic Drive |
| Surface | Dirt, Gravel, Sand |
| Features | Camping, High Altitude, Remote, Scenic |
| Length (miles) | 28 mi / 45.1 km |
| Duration | Half day |
| Max elevation (ft) | 7200 ft |
| Best season | May-October |
| Minimum vehicle | High-clearance AWD or 4WD |
| Nearest town | Mammoth Lakes, CA |
| Land manager | Inyo National Forest — Mammoth Lakes Ranger District |
| Permit required | No |
| Cell service | Spotty |
| Water crossings | No |
| Dispersed camping | Yes |
| Official sources | USFS Inyo National Forest road info |
| Start coordinates | |
| End coordinates | |
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Location
Trail Conditions
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Frequently asked questions
Can a stock Subaru Outback or AWD crossover handle this trail?
Probably yes on a dry summer day — the route is graded dirt and gravel with no serious obstacles. That said, soft sand sections and washboarding can catch low-clearance AWD vehicles off guard, so a high-clearance AWD or 4WD is the honest minimum.
When does the trail typically open and close each year?
May through October is the reliable window. Snow can linger on the caldera floor into spring and mud after early-season rain can make the sandy sections a mess — check with the Mammoth Lakes Ranger District before heading out before Memorial Day.
Do I need a permit or pass to drive this route?
No permit required and no day-use fee. You're on Inyo National Forest roads, so standard forest rules apply — no fees just to drive or camp dispersed.
What's the hardest section and what should I actually expect?
There's no genuinely hard section — this is an easy route. The worst you'll hit is loose sand near the Owens River corridor and some washboard that'll rattle your teeth if you're going too fast. It's a 'get out and explore' drive, not a technical challenge.
How far is the nearest gas station and is there water on route?
Fill up in Mammoth Lakes before you leave — it's your last guaranteed fuel stop, roughly 10–15 miles from the trailhead. There's no reliable potable water on the route itself, so carry everything you need for the day.
Trail track
No GPX track for this trail yet. If you've driven it and have a track, contribute below.
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