Illinois River 20 miles (32 km) of its course, the Illinois is separated from the Mississippi River by only about five miles, by a peninsula of land that makes up Calhoun County. The Illinois joins the Mississippi near Grafton, approximately 25 miles (40 km) northwest of downtown St. Louis and about 20 miles upstream from the confluence of the Missouri River and the Mississippi. South of Hennepin, the Illinois River is following the ancient channel of the Mississippi River. The Illinoian Stage, about 300,000 to 132,000 years ago, blocked the Mississippi near Rock Island, diverting it into its present channel. After the
Olifants River (Southern Cape) the east and flows westwards between the Swartberg and Kammanassie mountains to its confluence with the Gamka River. The southern slopes of the Swartberg Mountains are drained by the perennial Groot River, Kango River, Grobbelaars River, Wynands River, Kansa River and Vlei River tributaries, which flow into the Olifants River. The Kammanassie River rises in the Outeniqua and Kammanassie mountains near Uniondale and joins the Olifants River upstream of Oudtshoorn. Olifants River (Southern Cape) Olifants River () is a river in the Klein Karoo area of the Western Cape, South Africa. It has its origins in the Traka and Kalkwal