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| Adlai E. Stevenson High School (IL) | C | 2 | | Lincolnshire District 125 | IL | |
| Beacon Academy | C | 2 | Illinois Regional | (Independent School) | IL | |
| Belvidere North High School | C | 2 | Illinois Regional | Belvidere Community School District 100 | IL | |
| Ed W. Clark High School | C | 2 | Nevada Science Olympiad | Clark County School District | NV |
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| Glenbrook South High School | C | 2 | Oakton Regional | Glenbrook 225 | IL | |
| Illinois Mathematics and Science Academy | C | 1 | | Illinois Mathematics and Science Academy | IL | |
| John Adams H. S. | C | 1 | State | South Bend Community School Corporation | IN | |
| Lake Central High School | C | 2 | State | Lake Central School Corp. | IN | |
| Lake Forest Academy | C | 2 | Illinois Regional | independent | IL |
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| Lisle Senior High School | C | 2 | Illinois Regional | Lisle CUSD 202 | IL | |
| Loyola Academy | C | 2 | Illinois State Science Olympiad | Roman Catholic Archdiocese of Chicago | IL | |
| Maine South High School | C | 1 | Illinois Regional | Maine Township District 207 | IL | |
| Maine Township High School District 207 | C | 1 | Illinois Regional | Maine Township High School District 207 | IL | |
| Marquette University HS | C | 2 | | Private | WI |
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| Mundelein High School | C | 2 | Illinois State Science Olympiad | 120 | IL |
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| Munster High School | C | 1 | State | School Town of Munster | IN | |
| Naperville North Varsity | C | 2 | COD | Naperville 203 | IL | |
| New Trier High School | C | | Illinois State Science Olympiad | New Trier Township High School District 203 | IL | |
| Niles West High School | C | 2 | Illinois Regional | Niles Township District 219 | IL |
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| University High School | C | 1 | SoCal Joint Regional | Irvine Unified School Distrcit | CA | |
| University High School | C | 1 | Illinois State Science Olympiad | Illinois State University | IL | |
| University of Chicago Laboratory Schools | C | 2 | Harper | Independent school | IL | |
| West High School | C | 2 | Belleville | Madison Metropolitan School District | WI | |
| Whiting High School | C | 2 | State | School City of Whiting | IN | |