🦇 Twin Caves

Twin Caves is a pair of cave entrances connected by a short river at the bottom of a sinkhole within the boundaries of Spring Mill State Park in Lawrence County, Indiana, United States. The river is an exposed section of a mostly-underground stream that originates as Mosquito Creek several miles southeast of the park, which sinks into the Upper Twin Cave system. The stream then comes out briefly at Twin Caves, and flows into the Lower Twin Cave, re-emerging briefly at Bronson Cave shortly to the northwest, then flowing into the Shawnee Cave System. The stream finally emerges at the Donaldson Cave entrance as a short tributary of Mill Creek, still within the park.