John Ackerman established the Minnesota Cave Preserve in 1989 to preserve, study, protect and to promote conscientious exploration and conservation of our unique underground wilderness.
From the beginning, John recognized the need to protect the fragile and timeless environment, both above and underground. Conservation has always been a prime tenet of the Minnesota Cave Preserve.

Feel free to contribute to the Minnesota Caving Club. Your donation is tax deductible, and every penny will be used for conservation projects!

The Minnesota Cave Preserve owns eight preserves in S.E. Minnesota and Northern Iowa, which provides access to 36 miles of cave passages. The properties encompass 45 caves, 724.4 surface acres and 1,300.33 acres of additional subterranean cave rights.

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Located in southeastern Minnesota, the Cave Farm consists of 702.9 scenic surface acres, combined with 192 additional acres of subsurface cave rights. To date, 38 caves have been discovered on the property, including the largest, Spring Valley Caverns.

Approaching almost 6 miles in length, Spring Valley Caverns is the largest privately owned cave in the state, and is the most extensive cave system on the Cave Farm.

After completely excavating all rocks and soil over the three sinkhole entrances to the cave, a sizeable building, mimicking natural limestone, was constructed. It serves as a gathering place for cavers, researchers and nature groups before embarking on their underground journeys.

A number of ground breaking studies have taken place in Spring Valley Caverns, the results of which have been published in notable resources such as the Smithsonian Magazine.

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Located in Iowa, just across the Minnesota border, The Minnesota Cave Preserve owns 5 surface acres and 200 acres of subsurface rights to 17.5 mile long Cold Water Cave. One hundred eighty-eight feet below the secure man made entrance lies one of the most prominent and most highly decorated cave systems in the Upper Midwest. This cave system, the 32nd longest in the United States, has been dedicated as a National Natural Landmark.
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Goliath's Cave is an extensive Fillmore County Minnesota cave system which was discovered, documented and surveyed by Minnesota cavers. Access to the cave had been banned after the government purchased it in 1988. In 2004 the Minnesota Cave Preserve acquired several surface acres above the cave, including 358 subsurface cave rights, and created a second entrance. The upper level of the cave has large dry passages, in contrast to the occasionally turbulent lower stream levels. Numerous underground stream tributaries conjoin within the lower level, and over thousands of years have sculpted a series of expansive winding passages. After numerous discoveries were made by the Minnesota Caving Club, the final surveyed length of the cave system stands at 2.39 miles.
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Located in southeastern Minnesota, the Minnesota Cave Preserve owns one surface acre above Tyson Spring Cave where a man made entrance was created. In addition, the Minnesota Cave Preserve owns 144.5 acres of subsurface rights to the cave system, it's picturesque natural spring resurgence and 4 outlying caves. The network of spacious pristine passages are currently being explored and mapped. It is estimated that this cave system is 4 to 5 miles in length. In 2008 cave explorers unearthed rare extinct ice-age bones, resulting in the most significant scientific finding in any Upper Midwest cave. Tyson Spring Cave is one of the most important Pleistocene sites in the Northern United States.
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Located in southeastern Minnesota, the Minnesota Cave Preserve owns one surface acre and 231 acres of subsurface rights to this amazingly diverse cave system. A wide stream meanders along the main cave passage, which is lined with unique formations, before it finally drops over a deep chasm and forms a fantastic roaring waterfall. This 2.84 mile long cave system was discovered by John Ackerman, Phil Gemenden and John Preston in 2006, and contained the largest bat sanctuary in any natural cave in the Tri-State area before White Nose Syndrome disease desecrated the population. The three species of bats that had relied on Bat River Cave for their roost sites were being studied and monitored by cavers and scientists as White Nose Syndrome disease spread through the population.
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Located in southeastern Minnesota, the Minnesota Cave Preserve owns 11 surface acres and 148 acres of subsurface rights to this complicated cave system. This cave was discovered in 2008, after a rare catastrophic supercell rain storm collapsed the roof of a tall dome. Explorers rappelled 50’ down into the cave and went on to discover possibly the largest rooms, passages, pits and domes in the Tri-State region. It is thought that this cave is part of the huge York/Odessa underground drainage system that explorers have been attempting to enter since the 1800’s. To date over 4 miles of passages have been explored, and cavers are searching for the connecting passage that may lead them into this drainage system. It is estimated that this system may contain 30-50 miles of cave passages.
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Located in southeastern Minnesota, the Minnesota Cave Preserve owns an amazing sinkhole, which had been excavated by hand in the 1930's in hopes of discovering a cave worthy enough to commercialize. The deep sinkhole on this 0.4 acre forested property had been abandoned a long time ago, and although it had been reported that a cave was indeed discovered here, all details were lost. The sinkhole had since collapsed, and it became John Ackerman's obsession to find out exactly what, or if, anything had been discovered at the base of this sinkhole.
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Located in Winona County, this southeastern Minnesota cave was commercialized and open for tours for a brief period during the mid 1960's. The Minnesota Cave Preserve owns 1.1 surface acres over the cave, along with 26.4 subsurface rights to this well decorated cave system. Work is in progress in an attempt to locate hidden passageways.
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