Illinois is not typically associated with dramatic hiking terrain, but the southern tip of the state harbors a genuine geological wonder. Garden of the Gods in the Shawnee National Forest is a collection of bizarre sandstone outcroppings — Camel Rock, Anvil Rock, Devil's Smokestack, and dozens more — that rise from the hardwood forest floor in Pope County, near the Ohio River. The formations are 320 million years old, shaped by eons of water, wind, and freezing.

The Observation Trail is a 1-mile loop that visits the most spectacular formations with minimal effort, making it accessible to almost all hikers. For more mileage and solitude, the Wilderness Trail extends deeper into the Garden of the Gods Wilderness Area for a 3.5-mile loop through a landscape almost entirely free of the crowds that flock to the overlooks. In autumn, the surrounding hardwoods turn brilliant red, orange, and yellow — the combination of fall color and ancient sandstone is genuinely stunning.

The Garden of the Gods is open year-round and is free to visit. Dogs are allowed on leash. The nearest town with services is Harrisburg, about 12 miles north. The overlooks are best in early morning light. In summer, arrive early; the 1-mile Observation Trail can get crowded midday. No permit required.