Mercer Caverns

Useful Information

Location: Near Murphys, 8 km from Angels Camp. I5, at Stockton onto Hwy 4 west, follow Hwy 4 through Angels Camp to Murphys, leave Hwy 4 at the Murphys Business District Exit.
(38.151511, -120.478237)
Open: Memorial Day to Labor Day daily 9-17.
Labor Day to Memorial Day Thu-Mon 10-16:30.
Closed Thanksgiving day, 25-DEC.
Fee: Adults USD 22, Children (3-12) USD 16.
Groups (10+): reductions avaliable.
Classification: SpeleologyKarst Cave
Light: LightIncandescent Electric Light System
Dimension: T=13 °C, H=90 %, L=1,033 m, VR=59 m, A=649 m asl.
Guided tours: D=45 min, L=400 m, St=440.
Photography: allowed
Accessibility: no
Address: Mercer Caverns, 1665 Sheepranch Rd., Murphys, CA 95222, Tel. +1-209-728-2101. E-mail: contact
Mercer Caverns, PO Box 509, Murphys, CA 95247-0509.
As far as we know this information was accurate when it was published (see years in brackets), but may have changed since then.
Please check rates and details directly with the companies in question if you need more recent info.


01-SEP-1885 discovered by Walter J. Mercer while looking for gold.
02-SEP-1885 Walter J. Mercer filed a mining claim on the cave to secure his ownership.
20-DEC-1886 he purchased an additional 40 acres from a Daniel Thompson.
1887 opened to the public.
01-NOV-1900 Mr. Mercer died at the age of 46, his wife Margarita Castruccia Mercer becomes owner.
1901 electric light installed, one of the first installed in a western commercial cave.
1910 improved stairs installed.
1946 purchased by Vivian and Sterling Carter.
1946 renamed Mercer Caverns.
18-APR-1965 purchased by Burke Malcom and Bruce Prather and closed for renovation.
05-JUN-1965 reopened.
1972 light system renovated.
1981 all support beams and timbers in the caverns replaced.
1982 exit opened.
NOV-1985 cave surveyed by Bruce Rogers, USGS, and Charmaine Legge and Paul Decker, Golden Gate Grotto.


Mercer Caverns was named after its discoverer, the gold prospector Walter J. Mercer. On a hot summer day, when resting in the shade under some bay trees near a limestone rock he felt a current of cool air. He saw dry grass around a small hole—about the size of his fist—where he felt a strong draft of cool air. A small rock he dropped into the hole was falling for a long time. So he went to a mining camp and came back with tools to enlarge the opening, a rope and some candles.

The first exploration was rather short, as the sound of falling dirt and rock at the entrance made him fear, the entrance could collapse again. But he visited a room which is now called the Gothic Chamber. It had masses of tree roots, which hang in clusters from ceiling to floor, which he interpreted as the decaying timbers of a lost mine. He also found some human bones, obviously bones of dead miners. He named the cave New Calaveras Cave, as calaveras is the Spanish word for skull.

Excavations revealed six humans, four adults, one child, and one infant. The cave was first known to a native Indian Tribe called the Yokuts, who used it as a mortuary cave. They brought the bodies to the opening and let them roll down inside. They were hunters and moved their camp to follow the game, the cave was forgotten and the entrance filled with leaves and rocks.

The cave was opened to the public immediately after its discovery and a little work on securing the entrance. The guest books, signed by paying customers, date back to September 1885. Mr. Mercer and Mr. E. E. Floyd, the teacher at the one-room school in Murphys, explored the cave and named the formations. They wrote a booklet called The New Calaveras Cave, between 1885 and 1886, which was published in 1887 by Bacon Company. During these early years, Mr. Mercer and his workmen installed wooden ladders with railings. Torches, oil lamps, and candles provided illumination. In 1901 electric light was installed, and in 1910 the ladders were replaced by stairs.

In 1946, the cave was purchased by Vivian and Sterling Carter from the Mercer family. They modernized the electric light and surrounding land, and changed the name to Mercer Caverns. They also planned to modernize paths and stairs, but this was not carried out.

In 1965, when the cave was purchased by Burke Malcom and Bruce Prather, they immediately closed the cave for renovation for some months. Finally, the 1910 stairways were replaced and the paths redone, the tour became much easier and safer. Continuous work at the cave included a new light system in 1972, the replacement of all wooden support beams in 1981, and the reopening of the exit in 1982.

The cave is renowned for a wide range of speleothems. Beneath the calcite based speleothems like stalactites, stalagmites, curtains and so forth, there are a range of aragonite minerals. The frost-like deposits are called Flos Ferri. The term describes a coral-like variety or habit of aragonite, not a mineral species, and translates iron flower. Despite the name, it is pure CaCO3 and does not contain iron in relevant amounts. This name was given to the mineral at its locus typicus (type locale), the iron mine MineErzberg at Eisenerz, Styria, Austria. Other names are aragonite coralloide, Eisenblüte, or Fiore di Ferro.