Twin Caves is part of the Shawnee Cave System located in Lawrence County, Indiana, within the boundaries of Spring Mill State Park. The system stretches just over three miles and includes Donaldson Cave, Bronson Cave, and Upper/Lower Twin Caves.
The park offers boat tours into Northern (Upper) Twin cave located in Spring Mill State Park. The tours last 20 minutes and go about 500 feet (150 m) back and turn around due to the rest of the cave system belonging to the Indiana Karst Conservancy.
The tours are operated by the Indiana Department of Natural Resources and are seasonal from Memorial Day - October.