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 (Massachusetts) of the Muddy River into the tidal Charles was much wider. It formed the eastern Brookline border with Boston and Roxbury (depending on the year), from Brookline's incorporation in 1705 until Boston's annexation of Allston–Brighton in 1873. The present form of the river and surrounding parks was created by the Emerald Necklace project, between 1880 and 1900. Under the direction of designer Frederick Law Olmsted, the project reclaimed marshland, creating sculpted and planted riverbanks. The Muddy River is mentioned by John Winthrop, in his famous "Journal of John Winthrop," as the site of an unidentified flying object in March 1638