Twin caves

Twin Caves consists of two cave entrances connected by an underground river and located in a sinkhole within Spring Mill State Park. The upper cave is accessible by boat and reveals the passages carved by flowing water over time.

The cave formed over thousands of years through water erosion in limestone layers beneath the surface. This natural process of cave formation continues to shape the passages today.

Boat tours are led by experienced guides who show visitors how underground rivers shape the cave and which plants and animals live inside. The guides explain how this natural space matters to the local ecosystem.

Boat rides are short and require no special knowledge or training, making them suitable for visitors of different ages. Sturdy shoes are helpful since the cave areas can be slippery.

The underground rivers keep the cave cool and damp year-round, hosting rare wildlife adapted to complete darkness. These blind fish capture the interest of both scientists and curious visitors.

Location: Lawrence County

GPS coordinates: 38.72436,-86.41000

Latest update: December 14, 2025 12:21