Cannonball Cave USA

Locally known as Davidson Spring, this natural wonder has also earned the name “Davidson’s Blue Spring.” The spring’s nomenclature hails from the Davidson family, early homesteaders in the vicinity, whose cabins once stood uphill and slightly north of the spring.

  • Region: Missouri
  • Coordinates: 37.0308, -90.415467
  • Depth: 300 ft
  • Remarks:
  • Type: Cave

The Dynamic Spring Flow

Pre-Dam Origins:

Before the Corps of Engineers constructed a dam, Davidson Spring flowed from the base of a rock cliff and meandered for about 300 feet before reaching the St. Francis River. Historical measurements from 1932 to 1939 recorded flow rates ranging between 27 and 51 million gallons per day.

Cannonball Cave – A Unique Dive Experience

Birth of the Cannonball Cave Name:

Divers affectionately refer to it as Cannonball Cave, owing to the presence of an old round-shot cannonball that once rested at the entrance. Likely repurposed as a boat anchor, this cannonball had broken off and found its place at the base of the cliff where the cave entrance resides.

Navigating the Cave’s Layout

Cave Layout and Restrictions:

The cave’s entrance poses a restriction, measuring approximately 2.5 feet high and 12 to 15 feet wide. Only the central portion accommodates back-mounted divers. Beyond the entrance, a large tunnel unfolds, leading to a pit located a little over 700 feet from the entrance. While there are several jumps along the way, they all reconnect to the main tunnel. There’s also a brief jump off the pit itself.

Mesmerizing Clay Formations

Unique Clay Formations:

Inside the cave, you’ll encounter stunning clay formations, especially in the upper tunnels. Some sections boast 15 or more layers of colored clay, creating a mesmerizing visual spectacle, unlike anything found elsewhere.

The Challenge of the Pit

Descending the Pit:

The pit descends steeply through a series of concentric rings, leading to a restriction at 280 feet. Divers have installed a 1/2″ rope to facilitate passage through this challenging section. The flow can range from mild in the fall to a strong current at other times, requiring careful navigation.

The Exploration Beyond

The “Mud Room” and “Deep Tunnel”:

Past the restriction, you’ll enter the “Mud Room,” a wide, low silty space. Further exploration reveals the “Deep Tunnel,” a spacious passage measuring 10 to 15 feet in height and width, extending for a little over 250 feet before encountering a third restriction at 365 feet.

Challenges and Seasonality

Water Temperature and Seasonal Challenges:

Davidson Spring’s water temperature remains relatively stable, typically between 55 to 57 degrees Fahrenheit. However, the lake water varies significantly, ranging from around 80 degrees Fahrenheit in the summer to approximately 40 degrees Fahrenheit in the winter. The diving season is limited, emphasizing the importance of good visibility and low flow for exploration.

Collaborative Dive Teams for Exploration

Teamwork in Exploration:

Exploring Davidson Spring’s depths is best undertaken by skilled dive teams like the OCDA (Ozark Cave Diving Alliance). Their collective expertise and resources ensure safer and more extensive explorations, surpassing what individual or small groups of divers can achieve independently.


How deep is Cannonball Cave?

Cannonball Cave extends to a depth of approximately 300 feet.

What is the water temperature inside Cannonball Cave?

The water temperature in Cannonball Cave typically ranges from 55 to 57 degrees Fahrenheit (around 13 to 14 degrees Celsius).

Is Cannonball Cave open for public exploration?

Cannonball Cave is accessible primarily to experienced divers and cave exploration teams. Public access may be limited, and diving should be done with proper qualifications and safety measures.

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