This Eastern Sierra lake hides thousands of stone columns, and it took an LA reservoir to uncover them

Some of the strangest rocks in California spent roughly 760,000 years buried, and the City of Los Angeles is the reason you can walk among them today. That’s not a metaphor. It’s a reservoir.

On the east shore of Crowley Lake, just off Highway 395 in the Eastern Sierra, thousands of pale stone columns stand along the waterline like the ruins of a temple nobody built. And for decades, nobody could quite explain them.

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What you’re actually looking at

Picture a cliff of soft, sandy-colored rock that’s been carved into a colonnade. Some columns are barely poking out of the bluff, others rise up to 20 feet, and many are ringed with grooves at roughly one-foot intervals, like someone stacked them by hand.

Walk underneath and it gets weirder. The columns hold up overhangs that form shallow, cave-like rooms, and from inside you’re looking out at the lake through a row of stone pillars. There are up to 5,000 of them, scattered across two to three square miles of shoreline.

A supervolcano started it, and a lake finished it

About 760,000 years ago, the Long Valley Caldera blew in an eruption more than 2,000 times larger than Mount St. Helens in 1980. It buried this whole basin in hot volcanic ash and pumice.

Here’s the part UC Berkeley geologists pieced together and published in 2015. Snowmelt seeped down into the still-hot ash, boiled, and rose back up as steam, and those concentrated paths of water and steam left behind minerals that made the rock along them harder than everything around it.

Then the softer ash just sat there, hidden, for hundreds of thousands of years. Enter the Los Angeles Department of Water and Power, which dammed the Owens River and created Crowley Lake in 1941. Waves lapping at the new shoreline slowly chewed the soft stuff away and left the hardened columns standing.

So yes, a water project for a city hours to the south accidentally uncovered one of the most surreal geology lessons in the state. Not bad for a reservoir!

Getting there is half the story

There’s no paved road, no sign, and no visitor center. You reach the columns on a maze of unsigned dirt roads on the lake’s east side, so bring an offline map and expect a few wrong forks.

We rolled up in Lucy, our VW bus, took one look at the deep ruts and sandy climbs, and parked. From there it’s about 4 miles round trip on foot, rated moderate, with roughly [[VERIFY: elevation gain — Hiking Project lists 345 ft, our 2025 Crowley post lists 515 ft; AllTrails page couldn’t be fetched]] of climbing, mostly following the old dirt track.

Here’s my one strong opinion: walk it even if your rig could make the drive. The sagebrush, the open sky, and the Sierra crest stacked up behind the lake are half the reason to come, and you’d miss all of it staring at ruts through a windshield.

The last bit drops down a steep, sandy slope to a pebbly beach, and then the columns are right in front of you. We spent way longer than planned weaving in and out of them. You can read our full guide to visiting the Crowley Lake Columns for more on the route.

Why fall is the move

The water level decides everything out here. When the reservoir runs high, the columns can go partly or fully underwater, and winter snow can bury the whole area, so the seasonally low water of spring and fall is the window to aim for.

Fall has another perk: cooler hiking weather on a route with basically zero shade. When we went, the mosquitoes attacked the second we stepped out of the van, so pack bug spray along with water and sun protection. There’s nothing out here, not even a bathroom.

Want to see the columns glow? Come early or late in the day, when low sun lights up every groove and throws long shadows through the little stone rooms.

Make a day of it

You’re already deep in volcano country, so pairing the columns with a soak just makes sense. Our list of natural hot springs near Mammoth Lakes is a good place to start.

Headed north on 395? Detour around the June Lake Loop, then keep going to the tufa towers at Mono Lake for another dose of “is this even real?”

Trip tips: grab a rental car to get out here, lock in your hotel before the good rooms are gone, or skip both and book a camper van instead.

So be honest: would you make the walk, or gamble on the drive? Tell us which camp you’re in.

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