Derrick Cave

Looking north toward the large ponderosa pine growing out of the main portal to Derrick Cave. slgwv (Atlas Obscura User)

Looking into west portal. slgwv (Atlas Obscura User)

"Upper deck" above old fallout shelter. slgwv (Atlas Obscura User)

Looking out the east portal. slgwv (Atlas Obscura User)

Steel door frame, leading into the site of the fallout shelter. slgwv (Atlas Obscura User)

Inside the former fallout shelter, looking back toward the steel door frame. slgwv (Atlas Obscura User)

"Second deck" in eastern part of cave, near the main portal. The green is algae. slgwv (Atlas Obscura User)

Looking toward skylight illumination from the west portal. slgwv (Atlas Obscura User)

Skylight on the west side. slgwv (Atlas Obscura User)

Inside on the west side. The green on the walls is algae, not an artifact. slgwv (Atlas Obscura User)

Continuation of the cave on the west. slgwv (Atlas Obscura User)

Inside on the west side. The green on the walls is algae, not an artifact. slgwv (Atlas Obscura User)

Looking toward the west portal. slgwv (Atlas Obscura User)

The area around Bend, Oregon has been the site of extensive volcanism, mostly of basalt, for much of recent geologic time. This had led to the abundant lavatube caves for which the area is famous. Lavatube caves form when a lava flow crusts over, but the still-molten interior drains out. They typically form in basalt, which is sufficiently fluid to drain. The most famous lavatube in the area is Lava River Cave [link: https://www.atlasobscura.com/places/lava-river-cave], but there are literally dozens of others, most of which are completely undeveloped.

Derrick Cave, named after an early rancher, is one of these, even though it was the focus of some incongruous activity in the mid-20th century. In 1963 it was a designated fallout shelter, with supplies of food and water cached behind a concreted-in steel door. The supplies, and even the door, have long since vanished; only the door frame remains. Also in the 1960s, several thousand pounds of steel rails were stashed in a passageway, to see if they could be detected by remote sensing. These rails are also all gone now, too.

The main entrance, marked by a large ponderosa pine growing out of the opening, is a scramble but is not technical. To the northeast (right) the cave is a “double decker,” with several discontinuous levels and skylights and a very “open” feel in the upper levels. It extends some 600 feet. The lowest level on this side was the site of the fallout shelter, and the steel door frame in concrete is still preserved.

To the southwest the cave has a very different feel, more like a “typical” lavatube such as Lava Cave. It is taller, and beyond the first section also has no skylights; bringing a light is imperative. This section is about 1200 feet long.

Know Before You Go

The BLM website gives directions. Note that these will be graded roads that will likely require high clearance in spots, and 4wd if wet. The cave is also likely to be completely inaccessible in winter.

As noted, even though the cave is completely undeveloped, no special caving skills are required, just reasonably good balance and the ability to scramble over rough terrain. The right equipment, however, is definitely a requirement. Bring a light, helmet, and hiking shoes or boots. A headband light, which leaves the hands free, is convenient. An (electric) lantern can also be useful to throw light more widely. Be sure to have a spare light, too. You don't need a rope as no rappels are necessary. A walking stick may also be handy. In addition, the cave is cool, even in the summer; a jacket will be appreciated.

Don't bring pets, food or drink into the cave, and use electric lights only; no propane or gas lanterns. Even though the northeast end of the cave was used for camping in the past, too, please no camping or campfires.

Please don't disturb the cave features.

[Note to editors: please delete the version of the source with the superfluous "pp." Thanks!]