List of longest caves

This list of longest caves includes caves in which the combined length of documented passageways exceeds 100 kilometres (62 mi).

In some of these caves, passageways are still being discovered.

The largest form in areas of karst landforms whose rocks dissolve easily.

Preferable conditions for karst cave formation are adequate precipitation, enough plants and animals to produce ample carbon dioxide, and a landscape of gentle hills which drains slowly.

[citation needed] The highest concentrations of long caves in the world are found in the Pennyroyal Plateau of southern Kentucky, United States, in the Black Hills of South Dakota, United States, and in the Yucatán Peninsula, Mexico.