Much of the landscape north and east of Redding was created by volcanic activity. The exterior layers of massive rivers of molten lava cooled and hardened, while the hot liquid interiors continued to flow, leaving hollow, empty tubes. Because of this, lava tubes exist in fairly large numbers throughout the region. The caves generally lie unnoticed until a weakened portion of the roof collapses, for example, leaving an entrance.

As with any off-road traveling experience, please Tread Lightly and do not leave behind any trash or supplies. Most of the following cave experiences are free. Due to its delicate nature, the Samwel Cave requires a visit to the Shasta Lake Visitor Center and a permit prior to entrance. Flashlights, comfortable shoes, light jacket, hard hat or climbing helmet, applicable permits, maps and brochures, water, and first aid kit are all required for any spelunking experience.