Mystery Cave and Forestville: The Story and What Is True

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Mystery Cave and Forestville is a Minnesota story with a documented core at Forestville/Mystery Cave State Park, near Preston, Fillmore County. The sources are named below.

HistoryKind of story
2Named sources
South Lakes and Bluff CountryRegion
Nov 1Checked, 2026

The Story
Its Home
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A story with a documented core.

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Mystery Cave and Forestville

People say there is a cave in the hills of southeastern Minnesota that nobody found until 1937. Its passages run underground for miles, and the air stays chilly even on a hot August afternoon. The cave is now part of a state park, and a restored 1800s village sits not far away. Visitors can take a guided tour into the dark, then walk above ground through a town that was left behind when the railroad went elsewhere.

What The Record Shows

The Minnesota DNR says Mystery Cave was discovered in 1937 and is Minnesota's longest cave, with more than 13 miles of passages, in the Driftless Area of Fillmore County, between Spring Valley and Preston. The DNR gives the cave temperature as 48 degrees Fahrenheit year-round, and its Minnesota Conservation Volunteer magazine says about 47 degrees; the two numbers differ by a degree. The magazine says of Minnesota's roughly 400 caves it is the only one protected as a state park. The DNR offers a one-hour scenic tour and longer caving tours in season. The 2026 tours page says tours resume May 8, 2027. Historic Forestville, an 1800s village inside the park, is run by the Minnesota Historical Society. We did not find a DNR or Minnesota Historical Society account of who found the cave in 1937 or how.

Sources: Mystery Cave tours (Minnesota DNR); Minnesota Conservation Volunteer, July-August 2023 (Minnesota DNR magazine).

A Note

Not confirmed: how the cave was found; we read only the 1937 date and its size. Cave tours are paused until May 8, 2027, per the DNR page, so check before you visit.

Its home: Mystery Cave tours (Minnesota DNR). Official page.

On this site: State Parks Passport, Historic Sites, South Lakes and Bluff Country Events.

Looked for and Not Found

Who found the cave and how

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Frequently Asked Questions

Is the story of Mystery Cave and Forestville true?

Is this a legend?

It is a story with a documented core. The facts are listed on this page with their sources.

Where do these facts come from?

From the named sources listed on this page: Mystery Cave tours (Minnesota DNR); Minnesota Conservation Volunteer, July-August 2023 (Minnesota DNR magazine).

Sources

Read on November 1, 2026. Stories are for fun; the facts come from these sources. How we check: editorial standards; spot a mistake? tell us.

Cite this page: It's Minnesota, “Mystery Cave and Forestville”, itsminnesota.com/legends/mystery-cave-forestville/ (updated 2026-11-01). By the It's Minnesota editorial team. Free to quote with attribution and a link to this page; data and tables are licensed CC BY 4.0.