Please note that the content of this book primarily consists of articles available from Wikipedia or other free sources online. The Volo Bog State Natural Area is a 1,150 acre (4.5 km²) quaking bog maintained by the Illinois Department of Natural Resources (Illinois DNR). It is a National Natural Landmark as the only remaining open-water quaking bog in Illinois. It is located on Illinois Route 59 south of Fox Lake, Illinois.The bog itself is 47.5 acres (0.2 km²) in size. It was originally a steep-sided lake created by the melting of a large chunk of glacial ice at the end of the Wisconsonian glaciation.