Enrollment
2,759
California · 2024-25 NCES data
High school (grades 9-12) · Rancho Cucamonga, CA
Los Osos High
Federal NCES profile for Los Osos High, including enrollment, faculty, free-lunch eligibility, demographics, and resource indicators - Resource Investment Index 39/100.
2024-25 NCES dataHigh school (grades 9-12)NCES 060816010605
👥 S:T ratio 3
📚 AP courses 85
🌟 Gifted program 70
🎓 Counselors 21
📋 Attendance 17
Scored 0–100 from federal NCES and CRDC indicators, resource allocation, not test scores. Full methodology →
The verdict
Los Osos High earns 39/100 on the Resource Investment Index, with class sizes larger than 73% of California schools. It is also one of the largest schools in California.
- #9 of 13
- public schools in Rancho Cucamonga · Resource Index
- 39
- Resource Index · Typical
- 24.2:1
- large classes for California
- 25.0%
- free-lunch eligible
Los Osos High has class sizes larger than 73% of California schools. Computed live against every California school reporting to NCES.
By Resource Investment Index, Los Osos High ranks #9 of 13 public schools in Rancho Cucamonga, CA.
School address
District: Chaffey Joint Union High · California
NCES ID 060816010605 Verify on NCES CCD record →
Teachers (FTE)
114.0
Federal CCD staff survey
Students per teacher
24.2:1
vs 21.5:1 California avg
+13% vs state
Free-lunch eligible
25.0%
vs 55.5% California avg
-55% vs state
Student-teacher ratio in context
How Los Osos High compares with California and U.S. medians
What stands out at Los Osos High
Los Osos High is a large high school in Rancho Cucamonga, California, enrolling 2,759 students.
Class loads run somewhat heavier than typical: 24.2:1 puts it in the larger third of California schools by student-teacher ratio.
Economic need runs somewhat below the state's typical profile, with 25.0% of students eligible for free meals.
By headcount it is one of the larger campuses in California, bigger than 99% of state schools at 2,759 students.
Its Resource Investment Index sits near the middle of the pack among 9,998 scored California schools.
Among 196 similarly sized, similarly resourced-need California schools statewide, it ranks #144, in the lower tier once campus size and economic need are matched.
Its student body is led by Hispanic or Latino (41%) and White (24%), more mixed than most schools in the state (diversity index 71/100).
On the academic-pipeline side it reports 17 Advanced Placement courses.
Counselor availability sits well past the ASCA benchmark, roughly 394 students sharing each counselor, though short of the most stretched campuses.
Chronic absenteeism is elevated: 33.4% of students missed 10% or more of school days (2021-22 Civil Rights Data Collection).
The federal civil-rights collection also records 4 expulsions at this campus for 2021-22.
Among Rancho Cucamonga's high schools, it stands alongside Rancho Cucamonga High (3,221 students): Los Osos High is smaller than that campus by headcount and runs leaner classes (24.2:1 vs 24.4:1).
Chaffey Joint Union High also operates Etiwanda High (3,446 students) and Rancho Cucamonga High (3,221 students) alongside Los Osos High.
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 Los Osos High compares
Los Osos High on the metrics families compare, against California and U.S. means.
| Metric | This school | vs California | California avg | U.S. avg |
|---|---|---|---|---|
| Students per teacher | 24.2:1 | ▲ 13% | 21.5:1 | 15.7:1 |
| Free-lunch eligible | 25.0% | ▼ 55% | 55.5% | 51.7% |
| Enrollment | 2,759 | top 1% | - | - |
Source: NCES Common Core of Data School-level CCD + state/national means from Public School Universe · 2024-25
24.2:1
Leaner classes than 6% of US schools, heavier class loads than most.
2,759
Bigger than 99% of US schools by enrollment, a large campus nationally.
Equity indicators (what these measure)
Economic need
25.0%
free-lunch eligible
- 55% below the California average of 55.5%
Below the 40% Title I threshold, among the lower-need profiles in the state; federal aid targets individual qualifying students rather than schoolwide programs.
Staffing depth
24.2:1
students per teacher
- 13% above state mean
Top 73% in California - lower ratio than 27% of state schools
Well above 20:1, one of the more stretched staffing loads nationally relative to enrollment.
Engagement
33.4%
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
$15,404
per pupil, district-wide
- below California avg of $16,509
Somewhat below the U.S. average per-pupil spend; funding constraints may affect programs, facilities, and staffing.
Support staff
Counselors7.0 FTE
Per 394 students, the combined health-and-guidance staffing load for this school.
Discipline context
6
in-school suspensions + 90 out-of-school
Suspension rate: 0.2 per 100 students. Combined in-school and out-of-school rate: 3.5 per 100 students. Reported via the Civil Rights Data Collection. Includes 4 expulsions.
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
Hispanic or Latino 41.4%
White 24.4%
Asian 23.0%
African American 5.9%
Two or More 4.9%
American Indian / Alaska Native 0.3%
Native Hawaiian / Pacific Islander 0.1%
Largest group: Hispanic or Latino at 41.4% of enrollment.
Student-body diversity index 71.0/100
Simpson diversity index - at 71.0, Los Osos High is more mixed than the California school average of 46.0.
Programs
AP courses offered 17
Gifted & talented Yes
Funding & spending
District-wide per-pupil expenditure for Chaffey Joint Union High, which includes Los Osos High.
$15,404
Per student
-7%
vs California
Avg $16,509
-7%
vs U.S.
Avg $16,593
Revenue mix
Local 35.9%
State 52.9%
Federal 11.2%
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 Los Osos High Compares to District-Mates
| School | Enrollment | Economic Profile | Student-Teacher Ratio |
|---|---|---|---|
| Etiwanda High | Similar size | Similar economic need | Similar S:T ratio |
| Rancho Cucamonga High | Similar size | Similar economic need | Similar S:T ratio |
| Chaffey High | Similar size | Higher economic need | Similar S:T ratio |
| Montclair High | Similar size | Higher economic need | Lower S:T ratio |
| Alta Loma High | Similar size | Higher economic need | Similar S:T ratio |
Comparisons are relative to Los Osos High's own figures; each column derives from NCES Common Core of Data.
Other Schools in This District
- Enrollment
- 3,446
- Students per teacher
- 24.6:1
- Resource Index
- 28/100
- Enrollment
- 3,221
- Students per teacher
- 24.4:1
- Resource Index
- 31/100
- Enrollment
- 3,127
- Students per teacher
- 22.8:1
- Resource Index
- 30/100
- Enrollment
- 2,515
- Students per teacher
- 22.5:1
- Resource Index
- 36/100
- Enrollment
- 2,386
- Students per teacher
- 24.6:1
- Resource Index
- 23/100
Similar high schools in Rancho Cucamonga
1 comparable high schools (grades 9-12) serving the same city.
Similar high schools statewide
Matched by enrollment size and by staffing ratio across all of California, not just this city - a different peer set than the local comparisons above.
Similar enrollment (~2,759 students)
Similar student-teacher ratio (~24.2:1)
Next steps
Verify locally before acting on Los Osos High's federal record.
- Compare Los Osos High against another school. Compare schools
- Chaffey Joint Union High'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 Los Osos High
How many students attend Los Osos High?
Los Osos High has 2,759 students enrolled. It is a high school in Rancho Cucamonga, CA.
What is the student-teacher ratio at Los Osos High?
The student-teacher ratio at Los Osos High is 24.2:1, which is 13% higher than the California average of 21.5:1 and 54% higher than the national average of 15.7:1.
What percentage of students receive free lunch at Los Osos High?
25.0% of students at Los Osos High are eligible for free lunch, compared to the California average of 55.5%.
What is the racial and ethnic makeup of Los Osos High?
The largest demographic group at Los Osos High is Hispanic or Latino at 41.4% of enrollment, in Rancho Cucamonga, CA. Its student body is more racially and ethnically mixed than most US schools, with a diversity index of 71.0/100.
What is the Resource Investment Index for Los Osos High?
Los Osos High has a Resource Investment Index of 39/100 (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 Los Osos High rank among public schools in Rancho Cucamonga?
By Resource Investment Index, Los Osos High ranks #9 of 13 public schools in Rancho Cucamonga, CA. This compares federal resource and staffing data among local peers; it is not a test-score or academic ranking. See all public schools in Rancho Cucamonga on the city page.
Is Los Osos High a good school?
Los Osos High earns 39/100 on the Resource Investment Index, with class sizes larger than 73% of California schools. It is also one of the largest schools in California. 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 Chaffey Joint Union High?
Besides Los Osos High, Chaffey Joint Union High also operates Etiwanda High (3,446 students), Rancho Cucamonga High (3,221 students), and Chaffey High (3,127 students). See the Chaffey Joint Union High 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.