To many, the most outstanding natural features of Arches are the park's geologic formations. Over 2,000 catalogued arches range in size from a three-foot opening (the minimum considered to be an arch), to Landscape Arch which measures 306 feet from base to base. Towering spires, fins and balanced rocks complement the arches, creating a remarkable assortment of landforms in a relatively small area.

Two unusual natural features common in Arches intrigue both scientists and visitors: biological soil crust and potholes. Biological soil crust is a living groundcover that forms the foundation of high desert plant life.

Potholes are naturally occurring basins or pools in sandstone that collect rainwater and wind-blown sediment. These potholes harbor organisms that are able to survive long periods of dehydration, and also serve as a breeding ground for many desert amphibians and insects. Both of these communities are very vulnerable to human impacts.