California’s deepest cave and its most decorated cave are six miles apart in Gold Country
Moaning Caverns holds the deepest single cave chamber open to the public in California — 165 feet down a spiral staircase, sixteen stories below a gift shop in the middle of Gold Country. Six miles away in Murphys, Mercer Caverns won a Grand Prize at the 1900 Paris World’s Fair for a crystal formation most visitors almost miss. Neither cave requires a rope anymore, and you can do both before dinner.
Gold miners stumbled onto Moaning Caverns in 1851, following a sound echoing out of a crack in the hillside near Vallecito. That moan came from water dripping onto rock formations just inside the entrance, and once the opening was widened for tourist access, most of the sound disappeared with it. The name stuck anyway.
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Moaning Caverns: the deep one
The standard Spiral Tour runs 45 minutes: wooden stairs, then a hand-built spiral staircase from the early 1900s, down to a chamber floor 165 feet below the surface. Off-trail, the cave keeps dropping to a total depth of 410 feet, but that stretch is reserved for the caving trip, not the walking tour.
Archaeologists have pulled human remains out of this cave dating back roughly 12,000 years, buried under mineral deposits that built up over thousands of years. Nobody’s fully settled how they got there — the Miwok people native to the region didn’t traditionally bury their dead in caves, which keeps the mystery part of the draw.
Want to crawl through passages named the Meat Grinder and the Birth Canal? The Expedition Trip runs about three hours and $95 per person, ages 12 and up, reservation required.
The regular Spiral Tour costs $22 for adults and $15 for kids 3 to 11. Moaning Caverns is open Thursday through Monday, 10 a.m. to 4 p.m. — it’s closed Tuesday and Wednesday, so plan around it.
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Mercer Caverns: the decorated one
A gold prospector named Walter Mercer found this cave in 1885, and it’s been running tours for nearly a century and a half since. The main draw sits 161 feet down: a formation called aragonite flos ferri, delicate enough that it won a Grand Prize at the 1900 Paris World’s Fair.
Getting down means 208 steps. Getting back up means 232, so pace yourself — and bring a light layer, since the cave holds a steady 55 degrees year-round no matter what it’s doing outside.
Tours run about 45 minutes and cost $24 for adults, $18 for kids 3 to 12. Through Labor Day, Mercer Caverns is open daily from 9 a.m. to 5 p.m.; the rest of the year it drops back to Thursday through Monday, 10 a.m. to 4:30 p.m.
Making a day of it
The two caves sit six miles apart on Highway 4, close enough to tour both in one afternoon without rushing either. Murphys’ gold rush Main Street has picked up enough wine-tasting rooms over the years that people compare it to a mini Napa.
Skip the tasting flight if you’re short on time. Calaveras County’s best afternoon isn’t in a wine glass — it’s underground, on two different staircases, in two caves discovered thirty-four years apart.
Got another twenty minutes? Head up Highway 4 to Calaveras Big Trees State Park, where a bear hunter named Augustus Dowd stumbled onto a grove of giant sequoias in 1852 — trees so big that nobody back east believed the reports until photos started circulating.
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.
Rules and fees change — always confirm current requirements before you go.
