This Minnesota state park has 13 miles of cave and a town frozen in 1899

Two worlds beneath the bluffs of Fillmore County

Southeastern Minnesota is not the first place most people picture when they think of caves.

But tucked between the small towns of Spring Valley and Preston, Forestville/Mystery Cave State Park holds two things that shouldn’t exist this close together: a 13-mile underground maze and a ghost town frozen in 1899.

You visit them at two separate spots, a few miles apart, and each one feels like walking into a completely different world. The 3,170-acre park keeps its best surprises just below the surface.

The glaciers skipped this corner of Minnesota

The land here looks nothing like the flat Minnesota most people know. Fillmore County sits in the Driftless Area, a region the last glaciers never touched.

Because the ice never came through to flatten and fill everything, the landscape kept its shape. Water went to work instead, carving streams, sinkholes, and cave passages out of the soft limestone bedrock.

The bluffs, the valleys, and the winding creeks you see above ground all came from the same slow process that carved the cave below your feet.

13 miles of passages run under the hill

Mystery Cave is the longest cave in Minnesota, with more than 13 miles of underground tunnels.

Water dissolved the rock over millions of years, cutting passage after passage through the limestone until the whole thing became a maze. Explorers found it in 1937, and new sections kept turning up for years after.

No matter what time of year you go, the cave holds steady at 48 degrees. In January, that feels warm.

In August, it stops you cold the moment you step inside.

Pack a jacket even in the middle of summer

Coming in from a hot July afternoon, that 48-degree air hits like stepping into a refrigerator, and it feels good. Your shirt is probably damp from the walk over.

The cave takes care of that fast. This temperature never changes, winter or summer, which makes it one of the more comfortable summer stops in the state.

Tours run during the warmer months, so the cool underground air is part of the appeal. Leave the light layers in the car and you’ll regret it by the first turn in the passage.

The one-hour Scenic Tour is a solid first stop

If this is your first time at Mystery Cave, start with the Scenic Tour.

It runs about one hour and follows three-quarters of a mile of paved paths and bridges lit to show the formations in sharp relief. Wheelchair users and anyone pushing a stroller can manage it without trouble.

The lighting crew did real work here: shadows fall across the rock in ways that make small formations look enormous. First-time visitors tend to move slowly through this section, and that’s exactly the right pace.

Stalactites, fossils, and rock that moves like water

The formations in Mystery Cave took shape over thousands of years, and many of them are still growing. Stalactites hang from the ceiling above you.

Stalagmites push up from the floor below. Between them, flowstone spreads across the walls in slow frozen waves, minerals left behind by water that crept across the rock for centuries. Keep your eyes on the walls too.

Fossils sit embedded in the limestone, remnants of ancient sea life from a time when this whole region sat under a shallow ocean.

The blue lake glows at the end of the tour

Near the end of the Scenic Tour, the passage opens onto an underground pool. Visitors call it Turquoise Lake, and the name fits.

The water glows a soft blue from the dissolved calcite that drifts through it.

The cave goes quiet at this point, and the stillness of the water makes the whole space feel deeper and farther away from the world above than anywhere else in the tour. This is the spot where most people reach for their cameras.

Give yourself a minute to just stand there first.

Crawl through tight passages on the Wild Caving Tour

The Scenic Tour has lights and pavement. The Wild Caving Tour has neither.

This four-hour experience takes you off the marked paths and through sections of the cave that stay raw and unimproved.

You will get on your hands and knees and work through passages where the ceiling drops to within inches of your back. The mud is real.

The dark is real. You need sturdy laced boots, and the park provides the rest of the gear.

This tour is open to ages 13 and up, and it earns every bit of its reputation.

A whole town stuck in the year 1899

A few miles from the cave entrance, Historic Forestville runs as a living-history village locked in 1899. The Minnesota Historical Society manages it, and the costumed guides here are not tour guides reading from notes.

They play specific people, former residents of the actual town, going through the motions of a specific day in a specific year. Forestville was a busy trade stop before the railroad came through and routed around it.

After that, the town faded. What the park preserved is what got left behind.

Step inside the Meighen family general store

The Meighen store is the center of the village, and it still holds original goods on its shelves. Walk through the house, the farm, and the barn.

Check in at the kitchen to see what the guides have going on the stove. If you want a more hands-on visit, the hired hands in the garden will put you to work.

The whole property runs at the pace of 1899, which turns out to be slower than you expect. That’s part of what makes it worth the time.

Follow the trails to Big Spring and the trout streams

Above ground, the park opens up into miles of hiking trails through forest and bluffs. Horseback riders have their own trails separate from the foot paths.

Three spring-fed streams run through the park, and anglers come specifically for the brown trout. The water runs cold and clear, the way trout like it.

Big Spring sits along one of the routes, worth a stop on any hike through this section. The mix of oak savanna, forest, and open prairie means the landscape keeps shifting as you move through it.

Bats roost in the cave and turkeys walk the fields

The park holds more life than most people expect. Bats roost in the cave and head out at dusk.

Wild turkeys work through the fields in the morning.

Owls and songbirds fill the tree line, and in spring, Virginia bluebells push up through the forest floor in patches.

The combination of prairie, savanna, and hardwood forest draws a wide range of animals into the same small area. Come in any season and you’ll find something different.

Spring gets the wildflowers. Fall gets the color.

Winter gets the quiet.

Visit Forestville/Mystery Cave State Park in Minnesota

To get to the cave section of the park, skip your phone’s GPS.

It sends drivers the wrong way with some regularity, and the road to the cave entrance is not where the map says it is. Follow the park’s posted signs instead.

The cave stays at 48 degrees year-round, so bring a jacket no matter when you go. Cave tours run during the warmer months, and reservations are strongly recommended, especially on summer weekends.

The park sits in Fillmore County between Spring Valley and Preston in southeastern Minnesota. Check the official website for current hours, tour times and admission prices before you head out.

This article was created with AI assistance and human editing.

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