Diepolder II USA

Diepolder II and Diepolder III are fascinating cave systems located on the Sand Hill Ranch Scout Reservation in Hernando County, Florida. These caves hold a unique history and are among the most exceptional discoveries in the Western Hemisphere.

  • Region: Florida
  • Coordinates: 28.517755, -82.52912
  • Depth: 360 ft
  • Remarks: Guided
  • Type: Cave

A Legacy of Exploration

History of Diepolder Caves:

The Diepolder caves were donated to the Boy Scouts after the Diepolder family’s passing in the mid to late 70s. Subsequently, the Florida Speleological Researcher’s (FSR) program was established, becoming the oldest working guide program today.

Unique Features:

Diepolder II, in particular, stands out as the deepest cave in the continental United States, with depths reaching approximately 365 feet, while Diepolder III reaches around 300 feet.

Dive Regulations and Safety

Guidelines for Safe Diving:

To ensure safety and responsible exploration, FSR has developed guidelines for diving operations within the Diepolder caves.

  • All divers must have full cave training through either the National Association for Cave Diving (NACD) or the National Speleological Society-Cave Diving Section (NSS-CDS). No exceptions are permitted.
  • Divers must provide proof of 100 cave dives, documented in a logbook or through the Abe Davis or Wakulla Award.
  • Trimix gas dives require appropriate trimix certification.
  • Divers must be members in good standing of FSR, Inc., with no exceptions.

Diving in Diepolder Caves

Exploring Sink #3:

Diving in Sink #3 is a unique experience, and for safety reasons, each guide can accompany no more than three guests at a time. To maintain this ratio, at least one guest must have a minimum of five visits to Sink #3 before diving.

Progressing to Sink #2:

To dive in Sink #2, divers must first complete a minimum of three dives in Sink #3. Within Sink #2, the ratio is limited to one guide with no more than two guests, and again, one guest should have at least five dives in Sink #2 beforehand.

Pioneers of Exploration

Early Explorers:

The Diepolder system’s exploration has a rich history, with pioneers like Sheck Exley, Dale Sweet, Bill Main, Steve Stratsma, Bill Gavin, Vaughn Maxwell, and others. These divers pushed the boundaries of cave exploration, including the use of mixed gases, leading to the discovery of hidden depths and chambers within the caves.

Discover the Diepolder Caves Today

For the most up-to-date list of Diepolder guides, please click here. Explore the rich history and unique underwater world of Diepolder II and Diepolder III caves, safely guided by experienced professionals.


How deep is Diepolder II cave?

Diepolder II cave is approximately 365 feet deep, making it the deepest cave in the continental United States.

What is the water temperature inside Diepolder II cave?

The water temperature inside Diepolder II cave can vary, but it is typically in the low 70s Fahrenheit (around 22 degrees Celsius).

Is Diepolder II cave open to the public?

Diepolder II cave is not open to the general public. Access is typically restricted to experienced cave divers who meet specific qualifications and safety standards.

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