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
Muddy River (Nevada) National Wildlife Refuge Complex. In another effort to help protect and preserve the fragile habitats in the Muddy Springs area, the Southern Nevada Water Authority (SNWA) and various environmental associations have organized an effort to conserve these species. The area was part of the Native American Paiute peoples homeland for centuries, with the Mojave to the south. "Moapa" is a Southern Paiute language word meaning "muddy"; although "Moapa River" was formerly the official name, local usage tended to translate the name, and it was made official in 1960. The Old Spanish Trail originally followed the Virgin River all the way