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
Muddy Creek (Lamine River) of Sedalia. The stream passes south of the community of Newland and enters the Lamine River just west of the Pettis-Cooper county line four miles north-northwest of Clifton City at . Muddy Creek was so named on account of its muddy water. Muddy Creek (Lamine River) Muddy Creek is a stream in Johnson and Pettis Counties in the U.S. state of Missouri. It is a tributary of Lamine River. The stream headwaters arise in southeastern Johnson County just east of the community of Sutherland and Missouri Route 23 at . The stream flows northeast and enters Pettis County about three