Bentonite Hills

The Bentonite Hills showcase layers of diverse colors including browns, reds, purples, grays, and greens created by the Brushy Basin shale member formations that create an otherworldly landscape resembling extraterrestrial terrain.

These geological formations were created during the Jurassic period approximately 140 million years ago when swampy and lacustrine environments led to the deposition of mud, silt, fine sand, and volcanic ash that eventually lithified into distinctive shale layers.

Often called Utah's Rainbow Mountains or simply Mars by visitors and social media users, these hills have gained recognition for their resemblance to Martian landscapes and serve as a filming location for space-related productions.

Access requires high-clearance vehicles via Hartnet Road, and visitors should check road conditions before traveling as bentonite clay becomes extremely slippery and impassable when wet, especially after rainfall or snowmelt.

The bentonite clay develops a distinctive popcorn-like texture through repeated cycles of wetting and drying, causing the surface to expand and contract while creating the nickname popcorn hills among local geologists.

Location: Wayne County

Address: Hartnet Road, UT, USA

GPS coordinates: 38.36167,-111.12797

Latest update: October 24, 2025 17:38