# Onyx Cave

- **Access:** Gated
- **Length:** 0.5 mi
- **Geology:** Permian limestone
- **Location:** Santa Rita Mountains, Santa Cruz County, Arizona
- **Entrance Count:** 1

Onyx Cave is a solutional cave system with about of passages formed in Permian limestone in the Santa Rita Mountains of Arizona. It is part of the Coronado National Forest. It was designated a National Natural Landmark in 1974.

**Source:** https://en.wikipedia.org/wiki/Onyx_Cave_(Arizona) (Wikipedia, CC BY-SA)