Southern Illinois the Ozarks of Missouri, is chiefly in southern Jackson, Union, northern Alexander and Johnson counties. The eastern area, more closely related to the Wabash Valley Seismic Zone, is mostly in northern Pope, southern Saline, Gallatin, eastern Johnson and southern Williamson counties. The Shawnee National Forest covers a large territory, including seven wilderness areas: Garden of the Gods, Bay Creek, Clear Springs, Bald Knob, Burden Falls, Lusk Creek, and Panthers Den. Of southern Illinois' rivers, only the Mississippi and the Ohio are navigable for modern commerce. The Big Muddy River, Marys River, Saline River and Cache River run their courses in
Vermilion River (Illinois River) in Illinois. Access to a stretch of river around a dam owned by Buzzi Unicem was temporarily barred in 2009 after two drowning deaths that occurred on June 23 and 26, respectively, as well as numerous other boating accidents. The river access was reopened in 2010. The following cities and towns are drained by the Vermilion: The following counties are drained at least in part by the Vermilion River: Vermilion River (Illinois River) The Vermilion River is a tributary of the Illinois River in the state of Illinois, United States. The river flows north, in contrast to a second Vermilion