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
Vermilion River (Illinois River) these as a single river that flowed in two directions. It is also possible that, in early settlement times, these rivers formed a canoe route between the Illinois River and Wabash River, with a portage through the marshes near Roberts. This may explain why the two rivers have the same name. The north-flowing Vermilion flows in a northerly direction from its origin in Livingston and Ford counties in north central Illinois, eventually emptying into the Illinois River, near Oglesby. Perhaps it is best known for its stretch of whitewater between Lowell and Oglesby, Illinois, which is one of few found