The Southern Illinois River-to-River Conference (SIRR) is a high school athletic conference represented by 12 schools in southern Illinois.

Around 1991, the Southwest Egyptian was approached by Benton, Herrin, Harrisburg, and West Frankfort for membership; these four schools were concerned over their small size relative to the other members of the South Seven Conference (where all four were then located) and sought out a conference more in line with their size.

Massac County (then an independent school) was approached about becoming a member, and in 1993 the Southern Illinois River-to-River Conference was formed.

Chester High School has taken their place in the Black Diamond Conference.

[1] On June 12, 2020, it was announced that Sparta High School will depart for the Cahokia Conference the 2020–2021 school year, and the 11 remaining members were looking into potential replacements.