Besides tours & trails in the world’s longest cave, this park with 2 rivers offers camping & hiking.
"Mammoth Cave National Park is located in the hilly countryside of south-central Kentucky and is a part of the Green River Valley. With over 400 miles of explored cave system, Mammoth is the longest known cave in the U.S. Visitors to the park can enjoy surface and subsurface exploration, canoeing the Green River, hiking, camping, and horseback riding." [Travel+Leisure]
National Park
Website: Mammoth Cave National Park
Address: 1 Mammoth Cave Pkwy, Mammoth Cave, KY 42259
Sources: Best National Park in Every State