Cave Guides
Ultimate Guide to Twin Caves, Indiana (Tours, Pricing, History, Map)

Ultimate Guide to Twin Caves, Indiana (Tours, Pricing, History, Map)

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Twin Caves is a pair of cave entrances connected by a short river at the bottom of the sinkhole and within the boundaries of Spring Mill State Park. The park offers boat tours from the Twin Caves into the southern cave entrance, known as the Upper Twin Cave. 

Ultimate Guide to Twin Caves, Indiana (Tours, Pricing, History, Map)

Twin Caves, Indiana

The Twin Caves Boat Tours are the most popular activity here. It is a 20 min boat tour that goes upstream for about 500 ft into the cave, turns around as the rest of the cave system belongs to the Indiana Karst Conservancy. 

History of Twin Caves


The Twin Caves is a part of Spring Mill State Park. Geologists classify part of Southern Indiana or Mitchell Plain as a karst region. The Karst regions are characterized by sinkholes, caves, and underground drainage systems. St Louis and St Genevieve limestone formations under the Mitchell plain are ideal for forming karst features.

When the water seeped through the many joints and along the bedding planes of the formations, the limestone gets dissolved away, leaving behind an opening. With time, the opening enlarges and eventually becomes a cave that may have an underground stream system fed through sinkholes. The perfect example of such a cave is the Twin Caves. 

In the case of Twin Caves, a couple of sinkholes caused the collapse of the cave ceiling, exposing the underground stream. This is known as the Karst Window as it allows us to see the underground stream. The stream continues for a short distance in subsurface drainage and emerges from the mouth of the Donaldson Cave as surface drainage. 

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Geological Cave Formations in Twin Caves

There are no unique geological formations inside the Twin Caves, but they display a special feature known as a karst window. It is formed when a cavern roof collapses and exposes the karst groundwater to the surface.

The cave entrance provides a small glimpse of the stream that flows through the Twin Caves and exits at the Donaldson Cave. The unique biology of the Twin Caves can be better understood on the boat ride at the Upper Twin Cave. 

Wildlife in Twin Caves

The endangered blind cavefish is a common sighting in the Twin Caves. Visitors can see them when they go into the caves on the popular boat tour. 

Download our FREE Twin Caves Guide (Unofficial) 

Is Twin Caves Haunted?

The Twin Caves are not haunted by any stretch of the imagination, but every year a fun event by the name of Haunted Village takes place at the Spring Mill State Park. It is a spooky event where the whole village is transformed into a haunted spectacle. It has nothing to do with real-life hauntings. 

How Big are Twin Caves?

The exact dimensions are unknown, but the Twin Caves is a relatively large cave. 

twin caves map

 Twin Caves Tours

You can tour the Twin Caves only by boat. The tour guides wear gloves, and all participants must use sanitizer, and nobody is allowed to touch anything outside the boat. The most unusual inhabitants of the cave are the Northern Blind Cavefish.

Since there is absolute darkness in the cave, these fishes have wonderfully adapted to their surroundings. However, the tourists can only see a few of these fishes. It is hard to spot them as they are small and only a few inches long. 

When the tour is deep inside the cave, the tour guide will turn off all the lights so that you can experience what it feels like to be in total darkness. You will not be able to see your own hands! It creates an eerie atmosphere. However, the natural darkness of the cave prevents any picture taking. You can click pictures when you are coming out of the cave and admire the beauty of the limestone walls. 

Caves Tour Prices and Discounts

You must buy the tickets for the caves tours in-person at the Twin Caves shack. Same-day reservations are only accepted, and the cost is USD 1 for ages 3 to 10 and USD 3 for ages 11 and above. You cannot make payments through credit cards. Children under three years of age are not allowed on this tour. 

Is Twin Caves Cold?

The caves have a constant temperature of 54 degrees F. 

What to Wear?

Since the best time to come here is between May and October, you can pack in light clothing. However, you may carry a light jacket as the inside of the cave sometimes feels a bit cold. 

Twin Caves Hours

You can visit the Twin Caves between 9 am and 5 pm. 

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What to Do at Twin Caves (Beside Tours)

The highlight of the caves is the boat tours. So after the tour gets over, you can spend some time exploring the other facets of Spring Mill State Park. You can arrange for a picnic with your friends and families at the designated picnic area, visit the Pioneer Village and view the 20 historic buildings, or check out the Grissom Memorial with wonderful exhibits honoring Virgil Grissom, the 2nd man in space for the US. 

Best Time to Visit the Caves

The best time to visit Twin Caves would be from May to October, as the Twin Caves boat tours take place during this time. 

How to Get to Twin Caves

The Twin Caves is a part of Spring Mill State Park. It is around 90 miles south of Indianapolis via IN-37 South and located just 3.5 miles east of IN-37 and Mitchell on IN-60. You need to take IN-37 to IN-60 E and turn left onto the park. 

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Hotels near Twin Caves

If you are looking for hotels near the caves, then you will not be disappointed. The first option would be the Spring Mill State Park Inn within the park’s premises. It is a historic inn with more than 70 rooms, an indoor/outdoor pool, and great dining options. 

If you plan to camp here, you can use the electric or primitive campsites for RV or tent camping. There is a camping store where you can get the last-minute needs that you might have forgotten to bring. 

If you are not a camping fan and there is no vacancy at the Inn, you can look at the other lodging options in the vicinity of the park, such as cabins, hotels, and vacation homes. 

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Visiting Twin Caves

Do you need more information before visiting the caves? Call (812) 849 – 3534 or email Spring Mill State Park Office through the form for an information packet. 

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