Size: 3,953 acres
Year Designated: 1990
Fast Fact: Illinois’ most-visited landmark.
Hundreds of millions of years ago, a giant inland sea covered present-day Illinois; as ancient rivers and streams flowed into the sea, they deposited sediment along the sea’s shoreline, which began to build up and form rock under its own weight. When a giant uplift occurred, the sea filled with sand and mud and fractured the area’s bedrock, exposing it to the elements. Over time, the rock wore away into the stunning geological formations—the canyons, bluffs and cliffs—seen at the Garden of the Gods Wilderness today.