Overview: A lava tube 30 feet high, 50 feet wide and 1/4 mile long, Derrick Cave was named for H.E. Derrick, a pioneer rancher in the Devils Garden area. Derrick Cave developed just south of the main vent for the Devils Garden Flows and was the route of most of the lava which spread south from the vent. In the 1960s, Derrick Cave was a designated nuclear fallout shelter with supplies of food and water. Know Before You Go: There are no facilities. The road to reach the Derrick Cave area is unpaved and minimally maintained. Most of the time, two-wheel-drive, high-clearance vehicles can get to the trailhead. However, four-wheel-drive, high-clearance vehicles may be required when the road is wet. During the rainy season and the winter months, the road may become impassable for all vehicles, even those with four-wheel-drive. The cave is quite cool; visitors should wear a jacket while exploring. Don't forget a light source. Battery powered lights are best, as long as they provide reliable illumination. Prohibited activities in and around natural caves: Defacing, removing or destroying plants, soil, rocks, minerals, or other cave resources, Digging, excavating, or displacing any natural or cultural features, Camping, Building campfires, using stoves, or smoking, Depositing or disposing of human waste in or near a cave, Discharging a firearm, air rifle, or paint gun, Possessing or discharging fireworks or other pyrotechnics, Bringing a domestic animal into a cave, Any activity that disturbs the environment within a 350 feet radius of a cave opening or any known cave passages.