Enrollment
411
Illinois · 2024-25 NCES data
High school (grades 9-12) · Aledo, IL
Mercer County High School
Federal NCES profile for Mercer County High School, including enrollment, faculty, free-lunch eligibility, demographics, and resource indicators - Resource Investment Index 35/100.
2024-25 NCES dataHigh school (grades 9-12)NCES 170139500018
👥 S:T ratio 43
📚 AP courses 60
🌟 Gifted program 30
🎓 Counselors 18
📋 Attendance 25
Scored 0–100 from federal NCES and CRDC indicators, resource allocation, not test scores. Full methodology →
The verdict
Mercer County High School earns 35/100 on the Resource Investment Index, with class sizes near the Illinois median. It is also less racially and ethnically mixed than most Illinois schools.
- #3 of 3
- public schools in Aledo · Resource Index
- 35
- Resource Index · Typical
- 14.2:1
- students per teacher
- 411
- students enrolled
Mercer County High School has class sizes near the Illinois median. Computed live against every Illinois school reporting to NCES.
By Resource Investment Index, Mercer County High School ranks #3 of 3 public schools in Aledo, IL.
School address
District: Mercer County School District 404 · Illinois
NCES ID 170139500018 Verify on NCES CCD record →
Teachers (FTE)
29.0
Federal CCD staff survey
Students per teacher
14.2:1
vs 14:1 Illinois avg
+1% vs state
Student-teacher ratio in context
How Mercer County High School compares with Illinois and U.S. medians
What stands out at Mercer County High School
Mercer County High School is a mid-sized high school in Aledo, Illinois, enrolling 411 students.
At 14.2:1, its student-teacher ratio sits close to the Illinois median, within a few percentage points of the 14:1 state norm, neither notably crowded nor notably small.
With 411 students, its enrollment sits close to the Illinois median campus size.
Its Resource Investment Index lands in the lower third of 3,845 scored Illinois schools.
Its student body is predominantly White (93% of enrollment), among the less diverse in the state (diversity index 14/100).
On the academic-pipeline side it reports 12 Advanced Placement courses.
Counselor access is stretched at roughly 411 students per counselor, well above the ASCA-recommended 250:1 ceiling.
Chronic absenteeism is elevated: 29.9% of students missed 10% or more of school days (2021-22 Civil Rights Data Collection).
Mercer County School District 404 also operates Apollo Elem School (362 students) and Mercer County Jr High School (270 students) alongside Mercer County High 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
How Mercer County High School compares
Mercer County 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 | 14.2:1 | ▲ 1% | 14:1 | 15.7:1 |
| Enrollment | 411 | top 44% | - | - |
Source: NCES Common Core of Data School-level CCD + state/national means from Public School Universe · 2024-25
14.2:1
Leaner classes than 55% of US schools, a middle-of-the-pack class size.
411
Bigger than 49% of US schools by enrollment, mid-sized for the country.
Equity indicators (what these measure)
Staffing depth
14.2:1
students per teacher
- 1% above state mean
Top 60% in Illinois - lower ratio than 40% of state schools
Close to the 15:1 benchmark most often cited for individualized attention.
Engagement
29.9%
chronically absent (missed 10%+ of school days)
At or above 20%, the commonly used threshold for "high" chronic absenteeism, signaling significant barriers to regular attendance.
Funding equity
$13,924
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
Counselors1.0 FTE
Per 411 students, the combined health-and-guidance staffing load for this school.
Discipline context
19
in-school suspensions + 8 out-of-school
Suspension rate: 4.6 per 100 students. Combined in-school and out-of-school rate: 6.6 per 100 students. Reported via the Civil Rights Data Collection.
Overview
- Common Core of Data (June 2026): enrollment, staffing, and the student-teacher ratio above.
- Civil Rights Data Collection: discipline counts and program access (AP, gifted, special education).
- F-33 School District Finance Survey: the district-wide per-pupil spending figures below.
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.
Student demographics
White 92.9%
Two or More 3.2%
Hispanic or Latino 2.2%
African American 1.0%
Asian 0.5%
American Indian / Alaska Native 0.2%
Largest group: White at 92.9% of enrollment.
Student-body diversity index 13.5/100
Simpson diversity index - at 13.5, Mercer County High School is less mixed than the Illinois school average of 38.9.
Programs
AP courses offered 12
Funding & spending
District-wide per-pupil expenditure for Mercer County School District 404, which includes Mercer County High School.
$13,924
Per student
-18%
vs Illinois
Avg $17,042
-16%
vs U.S.
Avg $16,593
Revenue mix
Local 53.6%
State 38.0%
Federal 8.3%
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.
How Mercer County High School Compares to District-Mates
| School | Enrollment | Economic Profile | Student-Teacher Ratio |
|---|---|---|---|
| Apollo Elem School | Similar size | No free-lunch data | Similar S:T ratio |
| Mercer County Jr High School | Smaller | No free-lunch data | Lower S:T ratio |
| New Boston Elem School | Smaller | No free-lunch data | Lower S:T ratio |
| Mercer County Elc | Smaller | No free-lunch data | Higher S:T ratio |
Comparisons are relative to Mercer County High School's own figures; each column derives from NCES Common Core of Data.
Other Schools in This District
- Enrollment
- 362
- Students per teacher
- 13.9:1
- Resource Index
- 34/100
- Enrollment
- 270
- Students per teacher
- 11.7:1
- Resource Index
- 42/100
- Enrollment
- 165
- Students per teacher
- 8.3:1
- Resource Index
- 32/100
- Enrollment
- 66
- Students per teacher
- 22:1
- Resource Index
- 12/100
Similar high schools statewide
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.
Similar enrollment (~411 students)
Next steps
Verify locally before acting on Mercer County High School's federal record.
- Compare Mercer County High School against another school. Compare schools
- Mercer County School District 404'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 Mercer County High School
How many students attend Mercer County High School?
Mercer County High School has 411 students enrolled. It is a high school in Aledo, IL.
What is the student-teacher ratio at Mercer County High School?
The student-teacher ratio at Mercer County High School is 14.2:1, which is 1% higher than the Illinois average of 14:1 and 10% lower than the national average of 15.7:1.
What is the racial and ethnic makeup of Mercer County High School?
The largest demographic group at Mercer County High School is White at 92.9% of enrollment, in Aledo, IL.
What is the Resource Investment Index for Mercer County High School?
Mercer County High School has a Resource Investment Index of 35/100 (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 Mercer County High School rank among public schools in Aledo?
By Resource Investment Index, Mercer County High School ranks #3 of 3 public schools in Aledo, 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 Aledo on the city page.
Is Mercer County High School a good school?
Mercer County High School earns 35/100 on the Resource Investment Index, with class sizes near the Illinois median. 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.
What other schools are in Mercer County School District 404?
Besides Mercer County High School, Mercer County School District 404 also operates Apollo Elem School (362 students), Mercer County Jr High School (270 students), and New Boston Elem School (165 students). See the Mercer County School District 404 district page for the complete list.
Related tools
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.