Spring Mill State Park is a state park in the state of Indiana. The park is located south of Bloomington, about east of the city of Mitchell on Indiana State Road 60. Established in 1927, it contains a settler's village, the Gus Grissom Memorial (with the accompanying Gemini 3 space capsule), a nature center, and campgrounds.
The park is located on the Mitchell Karst Plain, which allowed the park's caves and sinkholes to form in the limestone. The caves include Bronson Cave, Twin Caves, Shawnee Cave (also known as Donaldson Cave), Hamer Cave, and others. A boat tour of Twin Caves is run by the Indiana Department of Natural Resources, which travels about into the cave.
A portion of the park is virgin timber, protected in the Donaldson Woods Nature Preserve. The Mitchell Karst Plain Nature Preserve is notable for its large number of sinkholes, more than 1000 per square mile. Many of the park's features were constructed by the Civilian Conservation Corps in the 1930s, including the Spring Mill Inn, Spring Mill Lake, and most of the trails. The park attracts about 675,000 visitors annually.
Pioneer village
A reconstructed pioneer village lies within the park, featuring a historic watermill and 19 other structures. It was the site of the original Spring Mill Village that developed around the mill from which it took its name, powered by a stream that arises from a spring in Hamer Cave. Heritage interpreters demonstrate crafts and skills from the 1860s. The Hamer Cemetery is located south of the village. This area was purchased from a cement company for a single dollar in 1923.