Inyo Craters: Ancient Volcanic Explosions Near Mammoth Lakes

June 18, 2026

Six hundred years ago, groundwater met partially molten rock deep beneath this forest and the result was catastrophic. The explosion that followed shot rock miles into the air, wiped out the surrounding trees, and carved three deep volcanic craters into the landscape north of Mammoth Lakes. Today those craters hold turquoise mineral lakes at the bottom of 200-foot walls of volcanic rock, and a well-marked trail reaches the rim in under a mile.

Located at the southernmost end of the active Mono-Inyo Craters volcanic chain, the Inyo Craters are one of the most accessible and visually dramatic volcanic features in the Eastern Sierra.

Inyo Craters at a Glance

Location: 3.5 miles north of Mammoth Lakes via Mammoth Scenic Loop
Trail: Inyo Craters Trail, 0.7 miles, easy to moderate
Best for: Sightseeing, geology, photography, fall color
Season: Year-round; road not plowed in winter, snowshoe or ski access only
No fee required

The Inyo Craters

The Inyo Craters were formed when groundwater contacted a large body of partially magmatic rock deep within the earth, generating steam and extreme amounts of pressure. The resulting cataclysmic explosion shot rocks miles into the air, wiped out the surrounding forest and left deep crater-like depressions as permanent scars on the landscape. It’s no coincidence that the Inyo Craters align with the volcanic remnants of nearby Obsidian Dome and the active Mono Craters—they are all part of the same geologically active system.

The Mono-Inyo Volcanic Chain

The Inyo Craters don't exist in isolation. They are part of a 25-mile volcanic chain that runs from the Inyo Craters in the south through Obsidian Dome and north to the Mono Craters and Panum Crater near Mono Lake. All of these features are connected to the same underlying magma system, and all formed within the past few thousand years, making this one of the youngest and most active volcanic landscapes in the continental United States.

The same volcanic system is responsible for the Earthquake Fault just south of here, a ground fracture formed during the same eruptive episode that created the Inyo Craters 600 years ago. It also connects south to Hot Creek Geologic Site, where the same deep magma body heats groundwater that emerges as geothermal vents in the gorge. The broader system sits on the rim of the Long Valley Caldera, the supervolcano that erupted 750,000 years ago and fundamentally shaped this entire landscape.

How to Get to the Inyo Craters

The Trail

The Inyo Craters Trail is a 0.7-mile trip that winds through old-growth ponderosa and Jeffrey pine on a mellow, family-friendly grade. The forest opens onto the chalky white rim of the southernmost crater. Mammoth Mountain and the jagged Minaret Range frame the view behind you. Below, a turquoise-green mineral lake sits at the bottom of a 200-foot-deep volcanic depression, its color drawn from dissolved minerals leaching from the crater walls. The second crater is just uphill from the first.

Keep an eye out for wildlife along the trail. The area supports a diverse bird population and a frequently sighted herd of mule deer.

In winter, the road is not plowed, but the craters make an excellent snowshoe or cross-country ski destination, sheltered from cold winds by the surrounding forest. Come fall, the stands of quaking aspen around the trailhead turn a vivid yellow, making this one of the more rewarding fall color stops near Mammoth Lakes.

Getting There

From Mammoth Lakes, travel west on State Route 203 toward Mammoth Mountain Main Lodge. After passing through The Village and continuing uphill, turn right onto the Mammoth Scenic Loop. Follow it for 2.5 miles to the Inyo Craters Road on the left. The trailhead parking area is one mile from the turnoff. A pit toilet is available at the US Forest Service-maintained trailhead and the path is well marked. No fee required.

Also Worth Seeing Nearby

Obsidian Dome: Part of the same Mono-Inyo volcanic chain, Obsidian Dome sits a few miles north along Highway 395. The 400-foot volcanic glass dome formed around 700 years ago, just decades after the Inyo Craters, when silica-rich magma cooled rapidly at the surface. The result is a mountain composed almost entirely of black volcanic glass, barren of vegetation and unlike anything else in the Sierra.

Earthquake Fault: A few minutes south along Highway 203, the Earthquake Fault is a ground fracture tied directly to the same volcanic eruption that formed the Inyo Craters. The Earthquake Fault Trail is an easy interpretive walk through old-growth conifers, and the two sites make a natural pairing for an afternoon of volcanic geology.

The Inyo Craters region rewards more than a single stop. Staying overnight in Mammoth Lakes puts the full length of the Mono-Inyo volcanic chain within easy reach, from the Earthquake Fault to the south all the way to Panum Crater and Mono Lake to the north. Browse lodging in Mammoth Lakes to plan your base.

aerial view of the Inyo Craters with pine forest and Mammoth Mountain in the backdrop

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