Volo Bog State Natural Area is a nature reserve in Illinois, United States, preserving Volo Bog. The bog was designated a National Natural Landmark in 1973 as the only remaining open-water quaking bog in Illinois. The site also contains woodlands, savanna, marshes, prairie restoration areas, shrubland and old fields. Maintained by the Illinois Department of Natural Resources, the site is located about a mile west of U.S. Route 12 between the towns of Volo and Fox Lake, Illinois.