Frequently Asked Questions

How far do you walk on the tour?
The walking distance of the tour is about a quarter of a mile. This distance is not covered all at once. There are several stops along the tour route where the guide will talk about the history and geology of the caverns and answer questions.

How many steps are there on the tour?
There are a total of 440 steps, 208 down into the caverns and 232 up out of the caverns. Many of the steps are along steep, narrow stairways so holding onto the handrails is always recommended.

How far down does the tour go?
The tour descends into the caverns to a low point of about 161 feet below the surface. This is the equivalent of a 16 story building. Currently, the lowest known point of the caverns is about 192 feet below the surface.

How strenuous is the tour?
The tour is moderately strenuous, mainly on the way out, due to the steepness of the stairs. Remember you will be climbing up stairs equivalent to a 16-story building but there will be stops along the way so it is not one continuous climb.

Do you have to crawl at any time during the tour?
There is no crawling during the tour although there are some areas where you must bend over and be careful not to bump your head, and there are some tight squeezes.

What is the temperature of the caverns?
The caverns maintain a constant temperature of approximately 55° Fahrenheit all year with a relative humidity of about 90%.

What kind of dress do you recommend?
We recommend that you wear comfortable nonslip walking shoes. We suggest that you avoid wearing sandals or flipflops as some of the steps have metal grates on them. We suggest that you dress in layers so that if you get a little cool you can put on a sweater or light jacket or if you start to warm up you can remove your sweater or light jacket.

Can you bring anything into the cave on the tour?
In order to preserve the cave environment and for safety reasons nothing is allowed to be carried into the caverns other than a still camera. No food or drinks are allowed into the caverns. No purses, bags, or backpacks may be taken into the caverns. Still cameras with flash are allowed on the tour. Video cameras and tripods are not allowed for safety reasons.

Do any animals live in the caverns?
The only known current inhabitants are blind white isopods. At one time gray squirrels and Western pipstrelle bats were regular inhabitants of the caverns but when the gates were installed to protect the caverns from vandalism the squirrels and bats did not return. Both squirrels and bats still live on the property but not in the caverns.

Is the cave still growing?
Some areas of the caverns still receive water causing formation growth but there are others that are dry where the formations are not growing.

Is there a map of the caverns?
The caverns were first mapped in October/November 1985 by Bruce Rogers, USGS, Charmaine Legge, and Paul Decker, all of the Golden Gate Grotto of the National Speleological Society. Bruce Rogers drew the only known map of Mercer Caverns. A copy of the map is on this website in the Cave Maps section.