Enrollment
139
Illinois · 2024-25 NCES data
Middle school (grades 6-8) · Mason City, IL
Federal NCES profile for Illini Central Middle School, including enrollment, faculty, free-lunch eligibility, demographics, and resource indicators - Resource Investment Index 43/100.
The verdict
Illini Central Middle School earns 43/100 on the Resource Investment Index, with class sizes smaller than 76% of Illinois schools. It is also less racially and ethnically mixed than most Illinois schools.
Illini Central Middle School has class sizes smaller than 76% of Illinois schools. Computed live against every Illinois school reporting to NCES.
By Resource Investment Index, Illini Central Middle School ranks #1 of 4 public schools in Mason City, IL.
NCES ID 170011305577 Verify on NCES CCD record →
Enrollment
139
Illinois · 2024-25 NCES data
Teachers (FTE)
12.0
Federal CCD staff survey
Students per teacher
11.6:1
vs 14:1 Illinois avg
-17% vs state
How Illini Central Middle School compares with Illinois and U.S. medians
Smaller classes than state median
11.6:1 - 2.4 below the Illinois state median of 14:1, indicating smaller average class loads than typical schools in the state.
Illini Central Middle School is a small middle school in Mason City, Illinois, enrolling 139 students.
Class sizes run a bit leaner than typical: 11.6:1 puts it in the smaller third of Illinois schools by student-teacher ratio.
This is a small campus: fewer students than 91% of Illinois schools, with 139 enrolled.
Its Resource Investment Index sits near the middle of the pack among 3,845 scored Illinois schools.
Its student body is predominantly White (96% of enrollment), among the less diverse in the state (diversity index 8/100).
Counselor coverage is strong, about 139 students per counselor, inside the American School Counselor Association's recommended 250:1.
Chronic absenteeism is elevated: 33.8% of students missed 10% or more of school days (2021-22 Civil Rights Data Collection).
Illini Central Cusd 189 also operates Illini Central Grade School (264 students) and Illini Central High School (172 students) alongside Illini Central Middle School.
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
Illini Central Middle 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 | 11.6:1 | ▼ 17% | 14:1 | 15.7:1 |
| Enrollment | 139 | top 91% | - | - |
Source: NCES Common Core of Data School-level CCD + state/national means from Public School Universe · 2024-25
Three separate federal collections, each on its own reporting cadence - which is why this school's numbers line up on a consistent basis against every other school and state on this site, rather than mixing figures pulled from different survey years.
Largest group: White at 95.7% of enrollment.
Simpson diversity index - at 8.3, Illini Central Middle School is less mixed than the Illinois school average of 38.9.
District-wide per-pupil expenditure for Illini Central Cusd 189, which includes Illini Central Middle School.
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.
| School | Enrollment | Economic Profile | Student-Teacher Ratio |
|---|---|---|---|
| Illini Central Grade School | Larger | No free-lunch data | Lower S:T ratio |
| Illini Central High School | Similar size | No free-lunch data | Lower S:T ratio |
| West Campus Facility | Smaller | No free-lunch data | Higher S:T ratio |
Comparisons are relative to Illini Central Middle School's own figures; each column derives from NCES Common Core of Data.
Matched by enrollment size and by staffing ratio across all of Illinois, not just this city - a different peer set than the local comparisons above.
Next steps
Verify locally before acting on Illini Central Middle School's federal record.
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.
Illini Central Middle School has 139 students enrolled. It is a middle school in Mason City, IL.
The student-teacher ratio at Illini Central Middle School is 11.6:1, which is 17% lower than the Illinois average of 14:1 and 26% lower than the national average of 15.7:1. Lower ratios generally mean more individual attention per student.
The largest demographic group at Illini Central Middle School is White at 95.7% of enrollment, in Mason City, IL.
Illini Central Middle School has a Resource Investment Index of 43/100 (typical reported resources relative to schools nationally) based on 4 factors: student-teacher ratio, counselor availability, attendance rates. Not a test-score or academic measure (national median ~41/100, see methodology).
By Resource Investment Index, Illini Central Middle School ranks #1 of 4 public schools in Mason City, 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 Mason City on the city page.
Illini Central Middle School earns 43/100 on the Resource Investment Index, with class sizes smaller than 76% of Illinois schools. It is also less racially and ethnically mixed than most Illinois schools. 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.
Besides Illini Central Middle School, Illini Central Cusd 189 also operates Illini Central Grade School (264 students), Illini Central High School (172 students), and West Campus Facility (65 students). See the Illini Central Cusd 189 district page for the complete list.
Every figure on PlainSchools is rendered directly from the source NCES, CRDC and F-33 federal records, no number is typed in by an editor. Each school's figures reflect its most recent NCES/CRDC submission on file. See our editorial standards & corrections policy, the methodology behind these numbers, or report a data error. Data current as of June 2026.
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PlainSchools, “Illini Central Middle School, Mason City IL.” Compiled from NCES Common Core of Data, Civil Rights Data Collection, and the NCES F-33 finance survey; data as of June 2026. https://plainschools.com/schools/illini-central-middle-school-il
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