Ohio River course forms the northern borders of West Virginia and Kentucky; and the southern borders of Ohio, Indiana and Illinois, until it joins the Mississippi River at the city of Cairo, Illinois. Where the Ohio joins the Mississippi is the lowest elevation in the state of Illinois, at . The Ohio River, which flows westward from Pittsburgh, Pennsylvania, to Cairo, Illinois, is the largest tributary, by volume, of the Mississippi River in the United States. At the confluence, the Ohio is considerably bigger than the Mississippi. Measured by long-term mean discharge in cubic feet per second and cubic meters per second,
Southern Illinois River-to-River Conference Southern Illinois River-to-River Conference The Southern Illinois River-to-River Conference (SIRR) is a high school athletic conference represented by 12 schools in southern Illinois. The conference is divided into two divisions. While technically in the same conference each division crowns its own champion, and each winner is regarded as the conference champion as if they were in two separate conferences. Schools are only required to play other schools within their own division although cross-divisional play is very common. Seven of the charter members of the River-to-River Conference were members of the old Southwest Egyptian Conference. Around 1991, the Southwest Egyptian was