Every public school, district, and the headline NCES measures for Illinois - 865 districts, drawn straight from federal records.
Compiled by PlainSchools, Education-data publisher
Scored 0-100 from federal NCES and CRDC indicators, resource allocation, not test scores - the same index shown on every school page, averaged across 3,845 scored Illinois schools. Full methodology →
The state in one line
Illinois runs 3,845 public schools across 865 districts, with a 14:1 average classroom and - of students on subsidized lunch.
3,845
public schools
865
school districts
14:1
avg student–teacher
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free/reduced lunch
What the NCES Data Says About Illinois Schools
Illinois operates 3,845 public K-12 schools organised into 865 independent school districts serving 1,844,783 students, per the National Center for Education Statistics Common Core of Data 2024-25. The largest district, City of Chicago Sd 299, enrolls 321,666 pupils across 644 schools at $22,699 per student, while smaller rural districts can run fewer than a dozen campuses. This fragmentation, inherited from century-old township governance patterns in many states, is why per-pupil spending, class sizes, and programme availability vary dramatically inside a single state boundary.
Statewide, the average student-teacher ratio is 14:1, a useful benchmark for comparing any individual district or school on PlainSchools. The district table below is sortable by enrollment, school count, and per-pupil expenditure, the three fields that best predict a district's financial and demographic profile. For schools specifically, use the rankings links above to view per-category leaderboards covering spending, student-teacher ratio, best schools by composite quality score, chronic absenteeism, and funding-equity distribution within the state.
Every district figure here pulls from two distinct federal surveys: enrollment and demographic data come from the NCES Common Core of Data 2024-25 (school membership and directory), while per-pupil spending, teacher salaries, and federal/state/local revenue shares originate in the NCES F-33 School District Finance Survey (FY 2022-23). Civil-rights indicators, gifted enrollment, AP course counts, counselor staffing, chronic absenteeism, in- and out-of-school suspensions, come from the 2021-22 Civil Rights Data Collection. Cross-referencing these three sources is what lets PlainSchools produce composite scores and equity rankings that single-source tools cannot.
Illinois's average student-teacher ratio vs. every US state
Average students per teacher, state by state (lower means more staffing per student)
14lower student-teacher ratio than 53% of 51 US states
Each bar is a band; taller bars hold more US states. The dashed line + filled bar mark this entry. Hover or tap any bar for its full count, share, and where it sits relative to this entry.
Source U.S. Department of Education, NCES Common Core of Data · 2024-25
Federal data, transparent formula.
PlainSchools publishes the actual federal survey data - enrollment, staffing, finance, and demographics from NCES. The diversity index and composite quality scores referenced on this page are PlainSchools' own transparent derived indices (not an official NCES rating), computed directly from those datasets with the exact formula disclosed on our methodology page; every input number traces to a cited source. These figures describe reported resource allocation across a large, varied state - a starting point for comparing districts and schools, not a substitute for reviewing a specific school's own record.
City of Chicago Sd 299 accounts for 17.4% of all Illinois K-12 enrollment
That concentration, well above the 8.4% national median for largest-district share, means state-level averages can mask substantial variation outside the dominant district. City of Chicago Sd 299 operates 644 schools serving 321,666 students, spending $22,699 per pupil. When one district dominates a state's K-12 footprint, its programmatic and budget decisions effectively set policy for a majority of the state's students.
Illinois per-pupil spending varies 5.8× across districts
Per-pupil spending in Illinois ranges from $8,725 (lowest district) to $50,605 (highest), a spread of $41,880. That spread reflects typical state-level variation between high-property-value suburbs and rural or low-tax-base districts. High-spending districts typically draw on higher property tax bases, a structural feature of state education finance under the federal Title I framework that sets the floor but not the ceiling.
Illinois operates 865 school districts, among the most fragmented K-12 governance structures in the country
Each district has independent budgeting, hiring, and curriculum authority. The fragmentation predates modern county-level consolidation efforts and reflects 19th-century township governance patterns, a feature of states that organised public schooling around small civic units rather than centralised state systems. Per-pupil spending and accountability variations are largest in fragmented states because each district sets its own tax rate, contracts, and programme mix without state-level coordination above the regulatory floor.
Average Illinois student-teacher ratio is 14:1 - near the U.S. average of approximately 16:1
Student-teacher ratio is the simplest staffing metric reported on NCES Common Core of Data, but it does not capture push-in specialists, intervention staff, English Language Learner aides, special education co-teachers, or counseling and support staff. Variation between districts within the state is wider than the state-average figure suggests, large urban districts may run 20:1 while small rural districts run 10:1, both inside the same average. Class-load comparisons are most meaningful at the district or school level, not the state aggregate.
Illinois's public schools average a Simpson diversity index of 38.9/100, below the national average of 43.5. The index runs 0-100 from NCES race and ethnicity data, where higher means a more evenly mixed student body. It measures mix, not quality. See where Illinois ranks in our national school-diversity analysis.
Data sourced from NCES Common Core of Data (CCD) 2024-25, NCES F-33 School District Finance Survey, and Civil Rights Data Collection (CRDC) 2021-22.
Using the Illinois data
Illinois's 3,845 schools sit inside 865 districts - compare at the district level first.
District boundaries decide enrollment: shortlist 2-3 districts on spending, ratio, and size before comparing individual schools. Compare districts →
Check how Illinois distributes money across its districts, funding equity varies more within states than between them. Funding equity →
Verify any school's federal record (enrollment, staffing, CRDC flags) before a visit or enrollment decision. Look up a school →
Figures are the federal record (CCD 2024-25, F-33 FY 2022-23, CRDC 2021-22) - they lag the current school year. PlainSchools assigns no subjective rating; the composite quality score used in our rankings is a transparent, reproducible index computed from this cited federal data.
Frequently Asked Questions
How many public schools are in Illinois?
Illinois has 3,845 public schools across 865 school districts, serving 1,844,783 students.
What is the average student-teacher ratio in Illinois?
The average student-teacher ratio in Illinois public schools is 14:1. This varies by district, use the district table below to compare.
What is the largest school district in Illinois?
The largest school district in Illinois is City of Chicago Sd 299 with 321,666 students across 644 schools.
Largest K-12 public schools by total students enrolled
students
Adlai E Stevenson High…
4,758
Adlai E Stevenson High School
4,758 students
100.0% of the leader · rank #1 · Lincolnshire, IL
Lane Technical High Sc…
4,604
Lane Technical High School
4,604 students
96.8% of the leader · rank #2 · Chicago, IL
Taft High School
4,487
Taft High School
4,487 students
94.3% of the leader · rank #3 · Chicago, IL
Waukegan High School
4,186
Waukegan High School
4,186 students
88.0% of the leader · rank #4 · Waukegan, IL
East High School
4,020
East High School
4,020 students
84.5% of the leader · rank #5 · Aurora, IL
Lyons Twp High Sch
3,706
Lyons Twp High Sch
3,706 students
77.9% of the leader · rank #6 · La Grange, IL
Lockport Township High…
3,678
Lockport Township High Sch East
3,678 students
77.3% of the leader · rank #7 · Lockport, IL
West Aurora High School
3,641
West Aurora High School
3,641 students
76.5% of the leader · rank #8 · Aurora, IL
What this shows The largest public schools in Illinois by enrollment, often statewide virtual academies or large consolidated campuses, so size here reflects reach, not quality.
Source: National Center for Education Statistics (NCES) Common Core of Data (CCD) - Public school universe · 2023-2024 Public K-12 school enrollment, demographics, and operational data; collected annually by NCES from state education agencies.