Metro East Sun

O'Fallon High School had the highest enrollment among St. Clair County schools, welcoming 2,497 students during the 2021-22 school year, according to the Illinois State Board of Education report.

Out of all the students welcomed in the 2021-22 school year, 51.6% of them were boys, and 48.4% were girls.

Data also showed that most of the students were white, representing 60.3% of the student body at O'Fallon High School.

Among the 82 schools in St. Clair County, Belleville East High School ranked second in enrollment with 2,464 students, while Belleville West High School welcomed 2,095 students to be ranked third in the 2021-22 school year.

O'Fallon High School is a part of O'Fallon Township High School District 203, which generally encompasses schools within St. Clair County with its main office in O'Fallon.

In the previous school year, O'Fallon High School had the highest number of students among St. Clair County schools.

In the 2021-22 school year, Illinois had roughly 1.9 million students enrolled across approximately schools. There were more than 130,000 teachers in the public schools, or roughly one teacher for every 15 students, compared to the national average of 1:16.

K-12 enrollment has been declining in Illinois for many years, reflecting demographic changes. Combined public and private K-12 enrollment dropped 3% between the 2019–20 and 2020–21 school years (60,900 students), far more than the typical 0.5% to 1.5% annual enrollment declines in Illinois over the last 5 years.

School name	City	Total Enrolment
O'Fallon High School	O'Fallon	2,497
Belleville East High School	Belleville	2,464
Belleville West High School	Belleville	2,095
East St. Louis Senior High School	East St. Louis	1,219
Mascoutah High School	Mascoutah	1,203
Belle Valley School	Belleville	980
Mascoutah Middle School	Mascoutah	927
Mascoutah Elementary School	Mascoutah	807
Cahokia High School	Cahokia	804
Scott Elementary School	Scott Air Force Base	737
Amelia V. Carriel Junior High School	O'Fallon	681
Freeburg Community High School	Freeburg	677
Whiteside Elementary School	Belleville	669
Fulton Junior High School	O'Fallon	649
Mason-Clark Middle School	East St. Louis	646
Delores Moye Elementary School	O'Fallon	637
Marie Schaefer Elementary School	O'Fallon	626
Smithton Elementary School	Smithton	553
Bluffview Elementary School	Dupo	533
Abraham Lincoln Elementary School	Belleville	519
Freeburg Elementary School	Freeburg	507
Whiteside Middle School	Belleville	505
Wingate Elementary School	Shiloh	480
Millstadt Consolidated School	Millstadt	473
East St. Louis-Lincoln Middle School	East St. Louis	469
William Holliday Elementary School	Fairview Heights	444
Estelle Kampmeyer Elementary School	O'Fallon	439
Wolf Branch Elementary School	Swansea	422
Westhaven Elementary School	Belleville	414
J. Emmett Hinchcliffe Senior Elementary School	O'Fallon	411
West Junior High School	Belleville	408
Katie Harper-Wright Elementary School	East St. Louis	398
Union Elementary School	Belleville	395
Central Junior High School	Belleville	361
Ellis Elementary School	Belleville	361
Wyvetter Younge School of Excellence	East St. Louis	357
Laverna Evans Elementary School	O'Fallon	356
Annette Officer Elementary School	East St. Louis	355
High Mount Elementary School	Swansea	345
Dunbar Elementary School	East St. Louis	335
Jefferson Elementary School	Belleville	329
Vivian Adams Early Child Center	East St. Louis	328
Central Elementary School	O'Fallon	314
Shiloh Middle School	Shiloh	314
Wolf Branch Middle School	Swansea	311
James Avant Elementary School	Washington Park	308
Illini Elementary School	Fairview Heights	303
Signal Hill Elementary School	Belleville	298
Lebanon Elementary School	Lebanon	275
Maplewood Elementary School	Cahokia	274
Douglas Elementary School	Belleville	271
Freeburg Primary Center	Freeburg	270
Lalumier Elementary School	Centreville	264
Penniman Elementary School	Cahokia	264
Elizabeth Morris Elementary School	Cahokia	262
Helen Huffman Elementary School	Cahokia	260
Estelle Sauget School of Choice	Cahokia	257
Dupo High School	Dupo	254
Marissa Elementary School	Marissa	254
Marissa Junior and Senior High School	Marissa	252
Millstadt Primary Center	Millstadt	247
Roosevelt Elementary School	Belleville	245
Joseph Arthur Middle School	O'Fallon	238
Shiloh Elementary School	Shiloh	232
Grant Middle School	Fairview Heights	231
Lebanon High School	Lebanon	226
Pontiac Junior High School	Fairview Heights	221
New Athens Elementary School	New Athens	217
Harmony Intermediate Center	Belleville	213
Oliver Parks 6th Grade School	Cahokia	213
Emge Junior High School	Belleville	192
Dupo Junior High School	Dupo	154
Washington School	Belleville	153
Henry Raab Elementary School	Belleville	152
Franklin Elementary School	Belleville	148
New Athens High School	New Athens	136
New Athens Junior High School	New Athens	130
Southern Illinois University Charter School of East St. Louis	East St. Louis	118
Lovejoy Elementary School	Lovejoy	108
St. Libory Elementary School	St. Libory	50
Lovejoy Technology Academy	Lovejoy	37
Lovejoy Middle School	Lovejoy	26