West of Fillmore in the high desert of Millard County, Utah, Tabernacle Hill rises from a landscape of ancient volcanic drama — lava flows, cinder cones, and a network of lava tubes formed thousands of years ago when flowing basalt cooled on the outside while still-liquid rock drained from within, leaving hollow tunnels beneath the hardened surface. The result is an accessible and genuinely remarkable underground exploration destination on BLM land with no entrance fee and no crowds.

The tubes themselves are the destination — dark, cathedral-quiet corridors of basalt with rough walls and ceilings that reflect the violent geology of their formation. A headlamp is essential — some sections receive natural light but the deeper sections are genuinely dark. Above ground the landscape is classic Utah high desert — lava rock, sagebrush, juniper, and the open sky that this part of the Colorado Plateau delivers in every direction. Desert lizards work the warm rock. Ravens and golden eagles are the common birds of prey overhead. The approach road passes through white sand dunes that sit in striking contrast against the dark volcanic rock — worth slowing down for on both the way in and the way out.

The Geology

Tabernacle Hill is part of the Black Rock Desert volcanic field — a geologically recent and volcanically active region of western Utah where basaltic eruptions occurred as recently as 1,000 years ago. The lava tubes at Tabernacle Hill formed during a period of active basalt flow when the outer surface of a lava river cooled and solidified while molten rock continued flowing inside — eventually draining out and leaving the hollow tube behind. The ceiling skylights formed where the roof section was thinner and eventually collapsed — creating natural light wells that make exploration of the tubes practical without complete reliance on artificial light.

Our Visit — September 20, 2017

A stop during our month-long trip that began in Utah — we had come from the south and were heading north, with Meadow Hot Springs as our next stop just a short distance away.

On the way in a group of cows at a cattle guard had decided the road was theirs — a welcome and completely unhurried blockade that reminded us whose country this actually is. Eventually they moved.

Luca, Alexis, and I explored one full tunnel and part of a second. The skylights were the highlight — sections where the ceiling has opened to the sky above, sending natural light down into the dark tube in columns that make the whole experience more visually interesting than a uniformly dark cave. The contrast between the deep dark of the unexplored sections and the dramatic shafts of light at the skylight openings is something photographs don't fully capture. We used flashlights throughout and would not have wanted to be without them in the darker sections.

On the way out we played on the white sand dunes along the approach road — a completely different textural and visual world from the dark basalt of the tubes, sitting alongside each other in the same high desert landscape.