Enrollment
684
California · 2024-25 NCES data
Elementary school (grades K-5) · Diamond Bar, CA
Castle Rock Elementary
Federal NCES profile for Castle Rock Elementary, including enrollment, faculty, free-lunch eligibility, demographics, and resource indicators - Resource Investment Index 26/100.
2024-25 NCES dataElementary school (grades K-5)NCES 064128006833
👥 S:T ratio 0
🌟 Gifted program 30
🎓 Counselors 0
📋 Attendance 72
Scored 0–100 from federal NCES and CRDC indicators, resource allocation, not test scores. Full methodology →
The verdict
Castle Rock Elementary earns 26/100 on the Resource Investment Index, with class sizes larger than 86% of California schools.
- #6 of 7
- elementary schools in Diamond Bar · Resource Index
- 26
- Resource Index · Lower
- 26.3:1
- large classes for California
- 24.9%
- free-lunch eligible
Castle Rock Elementary has class sizes larger than 86% of California schools. Computed live against every California school reporting to NCES.
By Resource Investment Index, Castle Rock Elementary ranks #6 of 7 elementary schools in Diamond Bar, CA.
School address
District: Walnut Valley Unified · California
NCES ID 064128006833 Verify on NCES CCD record →
Teachers (FTE)
26.0
Federal CCD staff survey
Students per teacher
26.3:1
vs 21.5:1 California avg
+22% vs state
Free-lunch eligible
24.9%
vs 55.5% California avg
-55% vs state
Student-teacher ratio in context
How Castle Rock Elementary compares with California and U.S. medians
What stands out at Castle Rock Elementary
Castle Rock Elementary is a mid-sized elementary school in Diamond Bar, California, enrolling 684 students.
Class loads run heavy: 26.3:1 is larger than about 86% of California schools and 22% above the 21.5:1 state mean, so each teacher carries more students than is typical.
Economic need runs somewhat below the state's typical profile, with 24.9% of students eligible for free meals.
Enrollment of 684 puts it in the larger third of California schools by headcount.
Its Resource Investment Index lands in the lower third of 9,998 scored California schools.
Among 1,319 similarly sized, similarly resourced-need California schools statewide, it ranks #979, in the lower tier once campus size and economic need are matched.
Its student body is led by Asian (70%) and Hispanic or Latino (19%) (diversity index 47/100).
Counselor access is stretched at roughly 684 students per counselor, well above the ASCA-recommended 250:1 ceiling.
11.1% of students were chronically absent in the 2021-22 collection, in line with the post-pandemic national range.
The surrounding Walnut Valley Unified spends $12,979 per pupil, 21% below the California average, a leaner-resourced district than most.
Among Diamond Bar's elementary schools, it stands alongside Evergreen Elementary (709 students): Castle Rock Elementary is smaller than that campus by headcount and runs heavier classes (26.3:1 vs 25.3:1).
Walnut Valley Unified also operates Diamond Bar High (2,563 students) and Walnut High (2,148 students) alongside Castle Rock Elementary.
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 Castle Rock Elementary compares
Castle Rock Elementary on the metrics families compare, against California and U.S. means.
| Metric | This school | vs California | California avg | U.S. avg |
|---|---|---|---|---|
| Students per teacher | 26.3:1 | ▲ 22% | 21.5:1 | 15.7:1 |
| Free-lunch eligible | 24.9% | ▼ 55% | 55.5% | 51.7% |
| Enrollment | 684 | top 25% | - | - |
Source: NCES Common Core of Data School-level CCD + state/national means from Public School Universe · 2024-25
26.3:1
Leaner classes than 4% of US schools, heavier class loads than most.
684
Bigger than 79% of US schools by enrollment, mid-sized for the country.
Equity indicators (what these measure)
Economic need
24.9%
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
26.3:1
students per teacher
- 22% above state mean
Top 86% in California - lower ratio than 14% of state schools
Well above 20:1, one of the more stretched staffing loads nationally relative to enrollment.
Engagement
11.1%
chronically absent (missed 10%+ of school days)
In the 10-15% range, above the pre-pandemic national baseline but within the broader post-pandemic picture.
Funding equity
$12,979
per pupil, district-wide
- below California avg of $16,509
Well below the U.S. average per-pupil spend, a notably leaner funding position that may affect programs, facilities, and staffing.
Support staff
Counselors1.0 FTE
Per 684 students, the combined health-and-guidance staffing load for this school.
Discipline context
0
in-school suspensions + 0 out-of-school
Suspension rate: 0.0 per 100 students. Combined in-school and out-of-school rate: 0.0 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
Asian 70.2%
Hispanic or Latino 19.3%
Two or More 5.4%
White 2.9%
African American 1.5%
Native Hawaiian / Pacific Islander 0.6%
American Indian / Alaska Native 0.1%
Largest group: Asian at 70.2% of enrollment.
Student-body diversity index 46.6/100
Simpson diversity index - at 46.6, Castle Rock Elementary is about as mixed as the California school average of 46.0.
Programs
Funding & spending
District-wide per-pupil expenditure for Walnut Valley Unified, which includes Castle Rock Elementary.
$12,979
Per student
-21%
vs California
Avg $16,509
-22%
vs U.S.
Avg $16,593
Revenue mix
Local 36.8%
State 54.5%
Federal 8.7%
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 Castle Rock Elementary Compares to District-Mates
| School | Enrollment | Economic Profile | Student-Teacher Ratio |
|---|---|---|---|
| Diamond Bar High | Larger | Similar economic need | Similar S:T ratio |
| Walnut High | Larger | Similar economic need | Lower S:T ratio |
| Chaparral Middle | Larger | Similar economic need | Higher S:T ratio |
| Suzanne Middle | Larger | Similar economic need | Similar S:T ratio |
| South Pointe Middle | Larger | Similar economic need | Similar S:T ratio |
Comparisons are relative to Castle Rock Elementary's own figures; each column derives from NCES Common Core of Data.
Other Schools in This District
- Enrollment
- 2,563
- Students per teacher
- 26.7:1
- Resource Index
- 48/100
- Enrollment
- 2,148
- Students per teacher
- 23.1:1
- Resource Index
- 52/100
- Enrollment
- 1,349
- Students per teacher
- 30.7:1
- Resource Index
- 41/100
- Enrollment
- 1,190
- Students per teacher
- 27:1
- Resource Index
- 43/100
- Enrollment
- 979
- Students per teacher
- 27.2:1
- Resource Index
- 47/100
Similar elementary schools in Diamond Bar
6 comparable elementary schools (grades K-5) serving the same city.
Evergreen Elementary
Standard public school
709 students 25.3:1 students per teacher
Quail Summit Elementary
Standard public school
696 students 27.8:1 students per teacher
Maple Hill Elementary
Standard public school
556 students 27.8:1 students per teacher
Pantera Elementary
Standard public school
512 students 24.4:1 students per teacher
Golden Springs Elementary
Standard public school
388 students 24.3:1 students per teacher
Armstrong Elementary
Standard public school
251 students 17.9:1 students per teacher
Similar elementary 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 (~684 students)
Similar student-teacher ratio (~26.3:1)
Next steps
Verify locally before acting on Castle Rock Elementary's federal record.
- Compare Castle Rock Elementary against another school. Compare schools
- Walnut Valley Unified'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 Castle Rock Elementary
How many students attend Castle Rock Elementary?
Castle Rock Elementary has 684 students enrolled. It is an elementary school in Diamond Bar, CA.
What is the student-teacher ratio at Castle Rock Elementary?
The student-teacher ratio at Castle Rock Elementary is 26.3:1, which is 22% higher than the California average of 21.5:1 and 68% higher than the national average of 15.7:1.
What percentage of students receive free lunch at Castle Rock Elementary?
24.9% of students at Castle Rock Elementary are eligible for free lunch, compared to the California average of 55.5%.
What is the racial and ethnic makeup of Castle Rock Elementary?
The largest demographic group at Castle Rock Elementary is Asian at 70.2% of enrollment, in Diamond Bar, CA.
What is the Resource Investment Index for Castle Rock Elementary?
Castle Rock Elementary has a Resource Investment Index of 26/100 (lower 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).
How does Castle Rock Elementary rank among elementary schools in Diamond Bar?
By Resource Investment Index, Castle Rock Elementary ranks #6 of 7 elementary schools in Diamond Bar, CA. This compares federal resource and staffing data among local peers; it is not a test-score or academic ranking. See all elementary schools in Diamond Bar on the city page.
Is Castle Rock Elementary a good school?
Castle Rock Elementary earns 26/100 on the Resource Investment Index, with class sizes larger than 86% of California 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 Walnut Valley Unified?
Besides Castle Rock Elementary, Walnut Valley Unified also operates Diamond Bar High (2,563 students), Walnut High (2,148 students), and Chaparral Middle (1,349 students). See the Walnut Valley Unified 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.