Apple River Canyon State Park preserves one of Illinois’s most distinctive unglaciated landscapes in Jo Daviess County. Its protected land encompasses much of an 8.5-mile canyon cut by the Apple River within the state’s Driftless Area, where rugged hills and valleys escaped the flattening effects of the last glaciation. Near the end of the last Ice Age, the river reversed its eastward course and began flowing southwest through an erosion gorge to the Mississippi, creating the deep canyon seen today. The park began with state land purchases in 1932 after a long campaign led by botanist Herman Silas Pepoon, linking its geological importance with a notable conservation effort.