Onyx Cave

Nature & parks
Near Rolla, Missouri
0.8 mi from Route 66
National Register of Historic Places

Onyx Cave is a natural cave near Newburg, MO, in the Rolla area of the Missouri Ozarks, which has also gone by the names Boiling Springs Cave and King Cave. Its main chamber is large, and its walls hold translucent cave onyx in white and cream shades. Miners once cut a shaft into it to reach that stone. It earned a spot on the National Register in 1999, a rare honor for a natural feature.

What is Onyx Cave?

The cave has one big room and two side passages. The main chamber runs roughly 250 feet long and 85 feet across, with a ceiling around 33 feet up. The onyx inside ranges from pure white to cream, and some pieces carry reddish bands.

Formations include stalactites hanging from the ceiling, stalagmites rising from the floor, columns where the two meet, and thin curtain-like draperies.

History of Onyx Cave

In 1892 a vertical shaft, about 8 by 13 feet, was dug so the onyx could be mined and hauled out. That industrial chapter is part of why the cave earned its historic listing in 1999.

Visiting Onyx Cave: tips

Public access is not confirmed here, so check locally before you make the trip, and never enter a cave without permission and proper gear. Boiling Spring Campground is under a mile away. The ghost town sites of Clementine and Hooker are about 1 and 2.5 miles off, and Arlington is about 4 miles.