The Devil’s Hole Boulder Caves (known locally as Devil’s Den), located 1.6 miles east of Bowmansville in Brecknock Township, are a natural and historical marvel. Situated at an altitude of 580 feet on the north side of the Yellow Hill Ridge, the caves are accessible from the southern edge of the Adventure Bound Oak Creek campground. Cross Oak Creek and follow the ascending southwest trail for approximately 1,300 feet. Here, you’ll find a slope covered with massive ironstone diabase boulders where the caves are hidden.
A Local Landmark With Storied Past
In addition to their geological significance, the Devil’s Hole caves are steeped in folklore. According to a 1940 Brecknock Township history edited by Charles Waters, during Dr. Charles Spotts’ youth, Bowmansville’s young residents often hiked to this natural wonder on Sunday afternoons. Known for its magnetic anomalies, the area causes compasses to deviate by 10–12 degrees due to ferruginous minerals in the ground.
Waters’ manuscript recounts dramatic tales of draft dodgers, bounty jumpers, horse thieves, moonshiners, and even murderers who used the caves as a hideout. The intricate system of boulders provided nearly perfect protection, with secret entrances leading to two large, dry rooms beneath the rocks. These rooms, described as approximately square and tall enough to walk in, became sanctuaries for those evading the law.
The caves’ secretive design offered a significant tactical advantage: intruders entering the narrow openings headfirst could be easily overpowered by those inside. Countless fugitives reportedly escaped capture by taking refuge in Devil’s Hole, making it a site of both mystery and survival.
Notable Features of the Boulder Caves
The Devil’s Hole Boulder Caves are the most extensive known diabase boulder cave system in Lancaster County and perhaps in Pennsylvania. Together, the largest caves feature over 210 feet of combined passages, separated by a mere 20 feet, with a shared stream flowing through them.
Boulder Cave No. 1
Located at the northwest edge of the boulder slope, this smaller cave, marked by painted letters in 1974 reading “The Den,” has a total passage length of 36 feet. A small, independent stream flows through this cave and eventually merges with larger streams below.
Boulder Cave No. 2
Approximately 130 feet southeast of Boulder Cave No. 1, this is the largest cave in the system. Entry requires navigating under a large diabase boulder and descending eight feet. From the entrance, a crawl northward leads to a keyhole passage, beyond which lies a low chamber where a segment of the stream is visible. The cave’s passages extend approximately 50 feet upstream and 50 feet downstream from this point, with a total known length of 160 feet. The dark, narrow passages are covered by 8 to 10 feet of boulders, with heights ranging from 2 to 6 feet.
Boulder Cave No. 3
Located near the base of the slope, 120 feet north of Boulder Cave No. 2, this smaller cave connects to the same stream. Exploration is possible for up to 40 feet upstream, but the passages become too tight to traverse further. Despite their proximity, Caves No. 2 and No. 3 remain physically unconnected.
The caves are part of a broad band of Triassic diabase that forms along the northeastern boundary of Brecknock Township. The Devil’s Hole caves, along with the nearby Silver Hill Boulder Caves, were formed by similar geological processes. The diabase, composed of feldspar and augite, fractured over time and was shaped by exfoliation—a weathering process in which layers of rock peel away like the layers of an onion.
This process, driven by seasonal temperature changes, hydration of minerals, and natural erosion, gradually reshaped and rounded the boulders. Post-Triassic faulting and debris removal by streams further enlarged the spaces between the rocks, creating the intricate cave systems we see today.
Note Well
When visiting any natural site, it’s important to respect private property and local regulations. Always seek permission from property owners before entering and follow any posted guidelines to ensure the safety and preservation of the area. By practicing responsible exploration, you help protect these unique places for future generations to enjoy.
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