Natural Wonders at Spring Mill State Park Near Mitchell, Indiana

Donaldson Cave, Bronson Cave, Hamer Cave, and Twin Caves are within the Spring Mill State Park boundaries; they are part of a larger limestone cave system. They are still "living" caves, still being actively developed by the flowing underground rivers and streams. You may find the caves are closed due to flooding if there has been recent rain. When conditions permit, you can take a guided boat trip into a section of Twin Caves. You'll see the endangered Northern blind cave fish that live in the cave as well as blind crayfish and some small bats. Usually spelunkers can enter other parts of the cave system, conditions permitting. However in 2009, only Twin Caves remains open for the boat tours. Donaldson Cave, Bronson Cave, and all other caves and sinkholes in the Indiana Department of Natural Resources system are closed as a precautionary measure against the spread of White-nosed syndrome. This is a fungal disease that is fatal to the cave bats, and it has spread rapidly from the New England areas westward, killing millions of bats in its path. You can read more about White-nosed syndrome here.

The nominal cost for the Twin Caves boat tour is only $3 per adult and $1 for children ages 3-11. Children must be at least 3 to ride. Tours last about 20 minutes and leave every half hour. On the day you will take your cave tour you should register early at the boat office for a time slot to help control visitor flow. On busy days the list fills up early. The temperature inside the cave is normally around 60 degrees or less, becoming cooler as you move farther in from the mouth of the cave. On a hot summer day, this is a wonderful way to cool off in Mother Nature's air conditioning!

The hiking trails in Spring Mill State Park are well marked. They loop and intersect, creating a great web of hiking opportunities. You'll find a range of trail difficulty, with a couple of fairly flat and easy walks, and some quite rugged climbs. The longest trail is only 2.5 miles long, and the shortest is a paved, wheelchair accessible trail that is .25 miles long. (This one is a nice walk if you have a baby in a stroller.) There is also a protected stand of virgin forest here in Spring Mill. If you have never seen truly huge trees in never-harvested areas of deciduous woodland, you must hike to the Donaldson Woods preserve area and experience the ethereal silence under the tall canopy of centuries old trees. Donaldson Woods borders on the area where the Twin Caves boat tours begin, so it is easy to find.

The Karst Plains Nature Preserve is an area of the park that has been set aside as a protected natural area. It is populated with many native wildflowers and plants, and is a small ecosystem that is in tune with the woodland and cave ecosystems. The park has a wide variety of native wildlife, including whitetail deer, opossums, raccoons, red and gray fox, coyotes, skunks, wild turkeys, and several species of water fowl.

Several picnic areas are located throughout the park, many with shelter houses that can be rented on a reservation basis. Some of these are massive stone and log structures, some with fireplaces.

The modern campground is shady and nice, with a group youth camp area available in a separate section. There are 187 electric campsites and 36 primitive sites. Mountain bikes are allowed on a dedicated two mile trail located near the campground, and you can even rent a bicycle if you don't bring your own. Bicycles are allowed on paved roads throughout the park, and there are bike lanes and one-way vehicle traffic for added safety. An Olympic sized pool, a wading pool, and bathhouse are near the campground. Swimming is allowed only in the pool.

There is a small camp store where you can purchase basics you may have forgotten, and firewood is sold there in bundles. If you come from certain counties and bring your own firewood, be prepared for it to be confiscated. Banning the import of firewood in many Indiana state parks is a measure to try to control the spread of the Emerald Ash Borer, a serious insect threat to hardwood forests that is making its way into central and southern Indiana.

Information about the historic Spring Mill Inn and the Nature Center can be found in this article.

Watch a slideshow about Spring Mill State Park

Read about the grist mill and the pioneer village here.