Geology of the National Parks

History of Arches

Double O Arch, NPS / Neal Herbert

Balanced Rock, NPS / Chris Wonderly


The geologic story of Arches National Park, located in eastern Utah, begins roughly 65 million years ago. At that time, the area was a dry seabed spreading from horizon to horizon. The striking red rock features we see today were thousands of feet below the surface. 

Geologic forces wrinkled and folded the buried sandstone causing fractures in the stone.

The entire region began to rise, climbing from sea level to thousands of feet in elevation.  Erosion carved layer after layer of rock away. Once exposed, deeply buried sandstone layers rebounded and expanded causing more fractures in the stone.

Today, water shapes this environment more than any other force. Rain erodes the rock and carries sediment down washes and canyons to the Colorado River.  Eventually this process turns fractured rock layers into arches, and there are more natural arches here than any other place in the world.

The area, designated a National Monument on April 12, 1929, became a National Park on November 12, 1971 when Richard M. Nixon was President.

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