Enrollment
2,540
Illinois · 2024-25 NCES data
High school (grades 9-12) · O Fallon, IL
O Fallon High School
Federal NCES profile for O Fallon High School, including enrollment, faculty, free-lunch eligibility, demographics, and resource indicators - Resource Investment Index 42/100.
2024-25 NCES dataHigh school (grades 9-12)NCES 172979003090
👥 S:T ratio 32
📚 AP courses 65
🌟 Gifted program 30
🎓 Counselors 27
📋 Attendance 56
Scored 0–100 from federal NCES and CRDC indicators, resource allocation, not test scores. Full methodology →
The verdict
O Fallon High School earns 42/100 on the Resource Investment Index, with class sizes larger than 87% of Illinois schools. It is also one of the largest schools in Illinois.
- #5 of 10
- public schools in O Fallon · Resource Index
- 42
- Resource Index · Typical
- 16.9:1
- large classes for Illinois
- 2,540
- students enrolled
O Fallon High School has class sizes larger than 87% of Illinois schools. Computed live against every Illinois school reporting to NCES.
By Resource Investment Index, O Fallon High School ranks #5 of 10 public schools in O Fallon, IL.
School address
District: O Fallon Twp Hsd 203 · Illinois
NCES ID 172979003090 Verify on NCES CCD record →
Teachers (FTE)
149.0
Federal CCD staff survey
Students per teacher
16.9:1
vs 14:1 Illinois avg
+21% vs state
Student-teacher ratio in context
How O Fallon High School compares with Illinois and U.S. medians
What stands out at O Fallon High School
O Fallon High School is a large high school in O Fallon, Illinois, enrolling 2,540 students.
Class loads run heavy: 16.9:1 is larger than about 87% of Illinois schools and 21% above the 14:1 state mean, so each teacher carries more students than is typical.
By headcount it is one of the larger campuses in Illinois, bigger than 99% of state schools at 2,540 students.
Its Resource Investment Index sits near the middle of the pack among 3,845 scored Illinois schools.
Its student body is led by White (59%) and African American (21%), more mixed than most schools in the state (diversity index 59/100).
On the academic-pipeline side it reports 13 Advanced Placement courses.
Counselor availability sits well past the ASCA benchmark, roughly 363 students sharing each counselor, though short of the most stretched campuses.
17.6% of students were chronically absent in the 2021-22 collection, in line with the post-pandemic national range.
The federal civil-rights collection also records 10 expulsions at this campus for 2021-22.
O Fallon Twp Hsd 203 operates only this one school, so O Fallon High School has no district-mates to compare against locally. At 2,540 students, it is also among the largest single-school districts in Illinois, well beyond the enrollment of a typical standalone charter.
Sourced from NCES CCD, CRDC, and F-33 (federal records, not a quality verdict). How we source and compute this.
Source: National Center for Education Statistics Common Core of Data + CRDC + F-33 · 2024-25
How O Fallon High School compares
O Fallon High School on the metrics families compare, against Illinois and U.S. means.
| Metric | This school | vs Illinois | Illinois avg | U.S. avg |
|---|---|---|---|---|
| Students per teacher | 16.9:1 | ▲ 21% | 14:1 | 15.7:1 |
| Enrollment | 2,540 | top 1% | - | - |
Source: NCES Common Core of Data School-level CCD + state/national means from Public School Universe · 2024-25
16.9:1
Leaner classes than 32% of US schools, heavier class loads than most.
2,540
Bigger than 99% of US schools by enrollment, a large campus nationally.
Equity indicators (what these measure)
Staffing depth
16.9:1
students per teacher
- 21% above state mean
Top 87% in Illinois - lower ratio than 13% of state schools
Between 16:1 and 20:1, squarely in the typical U.S. public-school staffing range.
Engagement
17.6%
chronically absent (missed 10%+ of school days)
In the 15-20% range, nearing the "high" absenteeism threshold.
Funding equity
$14,386
per pupil, district-wide
- below Illinois avg of $17,042
Somewhat below the U.S. average per-pupil spend; funding constraints may affect programs, facilities, and staffing.
Support staff
Counselors7.0 FTE
Per 363 students, the combined health-and-guidance staffing load for this school.
Discipline context
271
in-school suspensions + 165 out-of-school
Suspension rate: 10.7 per 100 students. Combined in-school and out-of-school rate: 17.2 per 100 students. Reported via the Civil Rights Data Collection. Includes 10 expulsions.
Overview
Enrollment 2,540 Top 1% in Illinois - larger than 99% of 3,845 state schools
Teachers (FTE) 149.0
Students per teacher 16.9:1 +21% vs state
Free-lunch eligible -
NCES ID 172979003090
Student demographics
White 59.3%
African American 20.5%
Two or More 9.5%
Hispanic or Latino 8.1%
Asian 2.5%
American Indian / Alaska Native 0.1%
Largest group: White at 59.3% of enrollment.
Student-body diversity index 59.0/100
Simpson diversity index - at 59.0, O Fallon High School is more mixed than the Illinois school average of 38.9.
Programs & staff
AP courses offered 13
Counselors (FTE) 7.0
Students per counselor 363:1
Discipline & special education
Chronically absent 17.6%
In-school suspensions 271
Out-of-school suspensions 165
Expulsions 10
Funding & spending
District-wide per-pupil expenditure for O Fallon Twp Hsd 203, which includes O Fallon High School.
$14,386
Per student
-16%
vs Illinois
Avg $17,042
-13%
vs U.S.
Avg $16,593
Revenue mix
Local 56.2%
State 37.9%
Federal 5.9%
Source: NCES F-33 School District Finance Survey District-level finance · FY 2021-22 Per-pupil expenditure reflects the district-wide average. Individual school budgets are not reported at the federal level.
Next steps
Verify locally before acting on O Fallon High School's federal record.
- Compare O Fallon High School against another school. Compare schools
- O Fallon Twp Hsd 203's spending and staffing shape this school. District profile
- Confirm current enrollment and boundaries with the school. Choosing guide
Federal record (CCD 2024-25, CRDC 2021-22) - PlainSchools assigns no subjective rating; the composite quality score is a transparent, reproducible index computed from this cited federal data.
Frequently asked questions about O Fallon High School
How many students attend O Fallon High School?
O Fallon High School has 2,540 students enrolled. It is a high school in O Fallon, IL.
What is the student-teacher ratio at O Fallon High School?
The student-teacher ratio at O Fallon High School is 16.9:1, which is 21% higher than the Illinois average of 14:1 and 8% higher than the national average of 15.7:1.
What is the racial and ethnic makeup of O Fallon High School?
The largest demographic group at O Fallon High School is White at 59.3% of enrollment, in O Fallon, IL. Its student body is more racially and ethnically mixed than most US schools, with a diversity index of 59.0/100.
What is the Resource Investment Index for O Fallon High School?
O Fallon High School has a Resource Investment Index of 42/100 (typical reported resources relative to schools nationally) based on 5 factors: student-teacher ratio, AP course offerings, counselor availability, attendance rates. Not a test-score or academic measure (national median ~41/100, see methodology).
How does O Fallon High School rank among public schools in O Fallon?
By Resource Investment Index, O Fallon High School ranks #5 of 10 public schools in O Fallon, IL. This compares federal resource and staffing data among local peers; it is not a test-score or academic ranking. See all public schools in O Fallon on the city page.
Is O Fallon High School a good school?
O Fallon High School earns 42/100 on the Resource Investment Index, with class sizes larger than 87% of Illinois schools. It is also one of the largest schools in Illinois. This is a resource snapshot, not an academic rating; see the Resource Investment Index question above for what the number does and doesn't measure.
What other schools are in O Fallon Twp Hsd 203?
None reported; O Fallon Twp Hsd 203 operates only O Fallon High School as a public school district in NCES's records.