Black Diamond Conference Former Members Former Members

| School | Location_ | Nicknames | Colors | Years_Member |
|---|---|---|---|---|
| Cairo High School | Cairo, Illinois | Pilots Co-Pilots | Blue White | 1992-2003 (affiliate) 2003-2008 |
| Carbondale University High School | Carbondale, Illinois | Lynxes | Maroon Gray | 1963–1968 |
| Carterville High School | Carterville, Illinois | Lions Lady Lions | Navy Blue Orange | 1949-1973 1975-2010 |
| Elkville High School | Elkville, Illinois | Bluebirds | Blue White | 1949-1962 |
| Sesser High School | Sesser, Illinois | Red Devils | Maroon White | 1949-1963 |
| Zeigler High School | Zeigler, Illinois | Purple Tornadoes | Purple White | 1949-1962 |