The Whigpistle Cave System near Mammoth Cave in Kentucky is a major network formed by Whigpistle, Martin Ridge, and Jackpot caves, mapped to more than 66 kilometers and ranking among the longest known cave systems in the United States. Discovered in 1976, it was first mapped under National Park Service supervision to study the hydrology of Mammoth Cave’s watershed, a role that remains central because of its close underground water connection to Mammoth Cave. Its notable features include the Big Womb, likely Kentucky’s largest cave chamber. Discoveries and new connections in the 1990s greatly expanded the known system, which is still being explored.