13 Ancient Limestone Caves Are Squeezed Into 6 Miles of Trails Inside Iowa’s Underground State Park

Maquoketa Caves State Park, Iowa

Maquoketa Caves isn’t your average state park hike. With 13 caves ready to explore, underground streams that vanish into rock, and limestone formations that’ll make you forget you’re in Iowa, this is real caving in the last place you’d expect. And you can explore it all at your own pace.

Raccoon Creek Shaped This Area

Raccoon Creek has cut through 430-million-year-old limestone to create cliffs that rise 200 feet from the creek bed. The valley further exposed Silurian bedrock strata exceeding 130 feet (40 meters) in thickness.

Today, 31 kinds of trees and 17 types of ferns grow in the valley. Seven springs flow from the caves into the creek. Cliff swallows and eastern phoebes nest in the limestone cliffs, while brook trout swim in the creek’s clean water.

People Lived in These Caves Long Ago

Digging in the caves has turned up evidence that Native Americans used them. People left behind stone tools (projectile points and scrapers), pieces of pottery, and bone tools that show they used these caves both for short hunting trips and longer stays.

In Upper Dancehall Cave, you can still see red ochre paintings on the deep cave walls. The Sagers Museum near Maquoketa Caves displays a variety of Native American artifacts, providing history about the indigenous peoples.

Cave Used to Host Dance Parties

Dancehall, the biggest cave in the park runs over 1000 feet and has ceilings as high as 40 feet in its main room. Back in the early 1900s, local farmers would gather here on Saturday nights to dance, using lanterns for light and bringing live music into the cave.

These days, electric lights run through the whole cave, making it the only fully powered space in the park. A concrete floor and aluminum railings make it easy for anyone to walk through.

A Natural Bridge Spans the Creek

From the 1.7-mile Upper Caves Trail, you’ll see a huge limestone arch rising 50 feet above Raccoon Creek. This natural rock bridge is 40 feet long, formed long ago when part of an old cave’s roof fell in.

Adjacent to the Natural Bridge is Balanced Rock, a notable 17-ton boulder precariously perched on a rock ledge. The area around it shows classic limestone features, with more than 40 sinkholes and chunks of exposed rock scattered across the land.

Wide Mouth Cave Lives Up to Its Name

If you’re above 4 feet and visiting Wide Mouth Cave (stretches 30 feet across), you’ll need to stoop first. This impressive cave opening formed when an old underground stream collapsed, and now it’s one of the most photographed spots.

Inside, the cave gets narrower to about 8 feet wide but stays a comfortable 12 feet tall. The cave extends back approximately 100 feet into three distinct rooms, including limestone columns and driftstone formations.

Bats Sleep in Crevices All Winter

Four kinds of bats make these caves their winter home. The caves stay between 48 to 54 degrees Fahrenheit, just right for bats to sleep through the winter from October to April.

Two types are prominent here: the little brown bat and the northern long-eared bat, both species are becoming rare. To keep the bats safe while they sleep, special gates at some cave entrances let bats fly in and out but keep people from disturbing them in winter.

The Cave System Goes On for Miles

While the park features a six-mile trail system, there are 13 named caves connected by smaller tunnels. It’s one of Iowa’s longest cave systems.

Some caves are suitable for walking, while others are better suited for serious spelunkers. The passages come in all sizes, from tight spots just 2 feet wide to big rooms 40 feet high.

The caves formed when rainwater slowly dissolved the limestone into dolomite bedrock.

See Rare Cave Formations Here

The park has unusual cave formations that you won’t find in many other Iowa caves. Look for helictites growing in spirals across Shinbone and Wye Caves that seem to defy gravity.

The walls of Hernando’s Highway drip with moon milk, soft white patches of crystals. In Dancehall Cave, you’ll find see-through curtains of flowstone that sparkle at night.

On the other hand hand, you’ll get to see classic karst topography and then fossils of crinoids and corals embedded in dolomite rock.

One Cave Stays Cool in Summer

Ice Cave is special because it stays around 33 degrees Fahrenheit even during warm months. The cave is shaped like a narrow upright tunnel that traps cold air inside.

You might see ice in this cave as late as June, which feels strange on a hot summer day. The cold air around the cave entrance creates a special environment where unusual plants like walking ferns and northern monkshood grow.

Major Upgrade in the 1930s

During the Great Depression, workers from the Civilian Conservation Corps (CCC) Company 2723 made the park much easier to explore.

They also put the first electric lights in Dancehall Cave with 1,500 feet of copper wire and made detailed maps that guides still use.

Additionally, the construction included rustic-style shelters and picnic areas that are still in use today for educational programs and gatherings.

Underground Streams Flow

Hidden streams run through the cave network, creating new tunnels as they flow. These underground waterways come out as seven springs in different parts of the park.

When it rains a lot, the water can create temporary waterfalls in Window Cave and Twin Arch Cave. Their home to special animals that have adapted to life without light, including the Northern cave-dwelling fish and several types of small types of troglobites.

Environment Creates Special Gardens

The caves make unique growing conditions that support over 250 species of vascular plants. Walking ferns grow near the cave entrance while around the deep sinkholes, you’ll find hardy plants like the northern monkshood.

Special types of mosses and liverworts grow where the limestone walls stay moist. The limestone cliffs also provide homes for rare plants like snow trillium and juniper moss, which are becoming hard to find in Iowa.