| 1884 | First game between to Illinois high schools is played as Chicago (Hyde Park) defeats Chicago (North Division). |
| 1940 | R. L. Baxter, Athletic Director and Peoria (Manual), organizes an invitational state tournament, held at Tom Connor (Caterpillar) Field in East Peoria. Belleville is the winner. |
| 1941 | IHSA takes over sponsorship of the tournament. |
| 1942 | Rain forces postponement of the title game, which is played a week later on the home field of Oak Park-River Forest H.S. before a record crowd of 3,000. |
| 1943 | For one season only, the state final field reduced to four teams because many schools cannot assemble a team. Title game rained out and played a week later at the home field of Morton Twp. before a record crowd of about 5,000. |
| 1954 | State championship game shortened from nine innings to seven. State final tournament moved to Woodruff Field in Peoria. Rain after the first two quarterfinal games forces tournament to be resumed the next week. |
| 1958 | State final tournament moved to Bradley Field in Peoria. |
| 1964 | State final tournament returns to Tom Connor Field in East Peoria after demolition of old Bradley Field. |
| 1970 | State final tournament moved to Meinen Field on the campus of Bradley University, Peoria. |
| 1974 | Rain forces postponement of tournament. Quarterfinal games played during week at Carpentersville and Springfield and finals played in Peoria the following weekend. |
| 1978 | State tournament split into two classes. Class A tournament held at Lanphier Park in Springfield. |
| 1980 | Class AA state final tournament moved to Lanphier Park in Springfield. |
| 1989 | Third-place game held for first time. |
| 1993 | Class AA state final tournament moved to Elfstrom Stadium in Geneva. |