| Name |
County |
| Oakland High School |
Coles County |
| Oakwood High School |
Vermilion County |
| Oblong High School |
Crawford County |
| Odin High School |
Marion County |
| O'Fallon Township High School |
St. Clair County |
| O'Fallon Township High School - Milburn Campus |
St. Clair County |
| Ohio High School |
Bureau County |
| Okaw Valley High School |
Moultrie County |
| Olympia High School |
McLean County |
| Ombudsman Chicago West High School |
Cook County |
| Oregon High School |
Ogle County |
| Orion High School |
Henry County |
| Orr Academy High School |
Cook County |
| Oswego East High School |
Kendall County |
| Oswego High School |
Kendall County |
| Ottawa Township High School |
LaSalle County |
| Our Lady of Tepeyac High School |
Cook County |
| PAEC High School |
Cook County |
| Palatine High School |
Cook County |
| Palestine High School |
Crawford County |
| Pana Senior High School |
Christian County |
| Paris Bridges School |
Edgar County |
| Paris Cooperative High School |
Edgar County |
| Paul Robeson High School |
Cook County |
| Paxton - Buckley - Loda High School |
Ford County |
| Peace and Education Coalition High School |
Cook County |
| Pecatonica High School |
Winnebago County |
| Pekin Community High School |
Tazewell County |
| Peoria Heights High School |
Peoria County |
| Peoria High School |
Peoria County |
| Peoria Notre Dame High School |
Peoria County |
| Peotone High School |
Will County |
| Percy L Julian High School |
Cook County |
| Perspectives High School of Technology |
Cook County |
| Perspectives Leadership Academy |
Cook County |
| Phillips Academy High School |
Cook County |
| Phoenix STEM Military Academy |
Cook County |
| Pinckneyville Community High School |
Perry County |
| Pittsfield High School |
Pike County |
| Plainfield East High School |
Will County |
| Plainfield High School Central Campus |
Will County |
| Plainfield North High School |
Will County |
| Plainfield South High School |
Kendall County |
| Plank Junior High School |
Kendall County |
| Plano High School |
Kendall County |
| Pleasant Plains High School |
Sangamon County |
| Polo Community High School |
Ogle County |
| Pontiac Township High School |
Livingston County |
| Pope County High School |
Pope County |
| Porta High School |
Menard County |
| Prairie Central High School |
Livingston County |
| Prairie Ridge High School |
McHenry County |
| Prarie Grove Junior High School |
McHenry County |
| Princeton High School |
Bureau County |
| Project Echo Alternative High School |
Williamson County |
| Project Indian - Alternative High School |
Grundy County |
| Prologue Early College High School |
Cook County |
| Prophetstown High School |
Whiteside County |
| Prospect High School |
Cook County |
| Prosser Career Academy |
Cook County |
| Providence Catholic High School |
Will County |
| Proviso East High School |
Cook County |
| Proviso West High School |
Cook County |
| Putnam County High School |
Putnam County |
| Quincy Notre Dame High School |
Adams County |
| Quincy Senior High School |
Adams County |
| Ramsey High School |
Fayette County |
| Rantoul Township High School |
Champaign County |
| Ray Graham Training Center High School |
Cook County |
| Reavis High School |
Cook County |
| Red Bud High School |
Randolph County |
| Reed - Custer High School |
Will County |
| Regina Dominican High School |
Cook County |
| Regional Alternative School |
Winnebago County |
| Regional Alternative School |
McLean County |
