Cave-in-Rock State Park Professional Review and Guide
"Few parks in Illinois can lay claim to as much fascinating history and even notoriety as Cave-in-Rock State Park, just east of the town of the same name on the Ohio River. From the 1790s to the 1830s, the 55-foot-wide cave in a bluff overlooking the river served variously as a hideout for counterfeiters, a lair for pirates who preyed on river traffic, and a “Liquor Vault and House of Entertainment.”
The cave itself is equally intriguing, and this is one place in southern Illinois where you’re sure to see flocks of tourists during the summer. Fortunately, most don’t spend the night, so the campground, while popular, is not nearly so crowded."