Southern Illinois Southern Illinois Southern Illinois (also known as "Little Egypt") is the southern third of the state of Illinois. The southern part of Illinois has a unique cultural and regional history. Part of downstate Illinois, the Southern Illinois region is bordered by the two most voluminous rivers in the United States: the Mississippi River and its connecting Missouri River to the west, and the Ohio River to the east and south with the Wabash as tributary. Southern Illinois' most populated city is Belleville at 44,478. Other principal cities include Alton, Centralia, Collinsville, Edwardsville, Effingham, O'Fallon, Harrisburg, Herrin, Mt. Vernon, Marion, and
Embarras River (Illinois) southeastern Champaign; the southern portion of the University of Illinois campus, including the small creek near the Vet Med Building; and Meadowbrook Park in south Urbana. The Embarras flows generally southward through Douglas, Coles, Cumberland, and Jasper Counties. In Jasper County, it turns southeast for the remainder of its course through Richland, Crawford, and Lawrence Counties. Portions of the river's lower course have been straightened and channelized. It joins the Wabash River southwest of Vincennes, Indiana. Along its course, the Embarras passes the towns of Villa Grove, Camargo, Charleston, Greenup, Newton, Ste. Marie, and Lawrenceville. The United States Board on