Enrollment
278
Elementary
DISTRICT 338 · STATE 405
SCHOOL COMMUNITY·MILLBURN TOWNSHIP SCHOOL DISTRICT·NCES 341020000230
South Mountain School
2 SOUTHERN SLOPE DRIVE, MILLBURN, NJ 07041 · (973) 921-1394 · Essex County
GRADES PK–04ELEMENTARY21-SUBURBREGULAR SCHOOL278 STUDENTS
Student : Teacher
9.7:1
29 FTE teachers
DISTRICT 11.8:1 · STATE 11.4:1
Free / Reduced Lunch
3%
8 students
DISTRICT 2% · STATE 41%
Community
0
0 members
Enrollment and student:teacher ratio compared against other elementary schools. Free/Reduced Lunch and demographics compared against all schools.
Enrollment by grade, 2024-25
| Grade | Students | Share |
|---|---|---|
| Pre-K | 42 | 15% |
| Kindergarten | 41 | 15% |
| Grade 1 | 45 | 16% |
| Grade 2 | 44 | 16% |
| Grade 3 | 49 | 18% |
| Grade 4 | 57 | 21% |
This year's kindergarten class (41) is 28% smaller than its 4th grade class (57).
Student demographics
62%Diversity index
The chance that two students picked at random belong to different racial or ethnic groups.
DISTRICT 63% · STATE 71% · US 70%
Student head counts by race/ethnicity from federal NCES enrollment data. District, state, and US figures are each group's share of all public school students in that area (US excludes territories). Very small groups may be suppressed in the source, so categories do not always sum exactly to total enrollment.
Gender split
School pathway
Students here typically continue to
Based on grade levels within Millburn Township School District. Attendance zones can vary; confirm enrollment with the district.
Test scores
NJSLA 2024-25 . % Meeting or Exceeding ExpectationsEnglish Language Arts
78.6%
NJ avg 53.1% . -5.7pp since 2023
Math
90.4%
NJ avg 41.6% . +1.1pp since 2023
What this means: On the NJSLA, New Jersey's statewide test, about 79 of every 100 students at this school read and write at grade level and about 90 of 100 do math at grade level. Across all New Jersey schools, those numbers are about 53 and 42. Reading and writing scores are down about 6 points since 2023, while math scores are up about 1 points.
NJSLA results by year
| School year | English Language Arts | Math |
|---|---|---|
| 2024-25 | 78.6% | 90.4% |
| 2023-24 | 84.3% | 89.3% |
% Meeting or Exceeding Expectations, all students and all tested grades.
Source: NJSLA. All students, all grades. See all years and grades →
BeatsExpectations
Demographically-adjusted score · methodologyTier
OUTPERFORMING
Top 10% of NJ schools after controlling for student poverty
Actual proficiency
85.4%
composite math + reading, all grades
Predicted
64.6%
based on NJ schools with similar FRL share
Beats by
+20.8pp
above demographic expectation
What this means: About 85% of students here test proficient in math and reading, well above the roughly 65% typical for New Jersey schools with a similar share of low-income students. BeatsExpectations ranks schools against others at the same poverty level, not by raw scores, so a school can post high scores and still fall short of its prediction, or post lower scores and still beat it. This school clears its prediction by about 21 points, placing it in New Jersey's top 10%.
BeatsExpectations runs a per-state regression of proficiency on free/reduced-lunch share, then scores each school by residual. How this is calculated →
Schools most like South Mountain School
South Mountain School's state test result (85.4% proficient) is higher than 2 of the 4 schools below with a result.
| School | Students | Low-income | Proficient |
|---|---|---|---|
| South Mountain School this school | 278 | 2.9% | 85.4% |
| Glenwood School SHORT HILLS | 315 | 1.0% | 93.7% |
| Barclay Brook School MONROE TWP | 332 | 9.3% | N/A |
| Wyoming School MILLBURN | 346 | 2.6% | 84.2% |
| Princeton Charter School PRINCETON | 423 | 7.8% | 89.1% |
| Hartshorn School SHORT HILLS | 392 | 0.8% | 83.5% |
Matched among New Jersey elementary schools on enrollment, the share of students from low-income families (eligible for free or reduced-price lunch), and racial and ethnic makeup. Proficient is the average share of students meeting the state standard across all of the school's state tests in 2023-24 and 2024-25, the same combined score our test-score rankings use. Online schools and schools serving specialized populations are not matched.
Where South Mountain School ranks
Among elementary schools| Measure | This school | In New Jersey | In Essex County |
|---|---|---|---|
| State test proficiency ranked highest first | 85.4% | #11 of 1,290 | #2 of 131 |
| Math proficiency ranked highest first | 90.4% | #10 of 1,319 ▲ 1 | #3 of 141 no change |
| Reading proficiency ranked highest first | 78.6% | #110 of 1,319 ▼ 66 | #21 of 141 ▼ 13 |
| Enrollment ranked largest first | 278 | #1,196 of 1,562 | #124 of 162 |
| Students per teacher ranked fewest first | 9.7:1 | #262 of 1,390 | #10 of 140 |
| Diversity index ranked most diverse first | 61.6% | #432 of 1,392 | #30 of 141 |
| Free and reduced lunch ranked highest share first | 2.9% | #1,395 of 1,481 | #130 of 142 |
| Enrollment change since 2017-18 ranked steepest decline first | -12.6% | #335 of 798 | #26 of 73 |
Ranked against other public elementary schools. Online schools are left out of every list, and test-score lists leave out schools that serve specialized populations. Each rank links to the full list. Arrows under a test-score rank show places moved since the prior test year, among schools tested both years.
4-year change
SY 2020-21 vs SY 2024-25Enrollment
278
+4 (+1%) vs 2020
+9% since 2000-01, when it was 256
Student : Teacher
9.7:1
was 9.8:1
Source: NCES Common Core of Data
Enrollment and staffing by year
| School year | Students | Teachers (FTE) | Students per teacher | Free and reduced lunch |
|---|---|---|---|---|
| 2024-25 | 278 | 28.8 | 9.7:1 | 3% (8) |
| 2023-24 | 285 | 29.8 | 9.6:1 | 2% (6) |
| 2022-23 | 284 | 29.7 | 9.6:1 | 2% (5) |
| 2020-21 | 274 | 28 | 9.8:1 | 1% (3) |
| 2017-18 | 318 | 26.7 | 11.9:1 | 1% (3) |
| 2015-16 | 361 | 30 | 12.0:1 | 2% (9) |
| 2010-11 | 387 | 30 | 12.9:1 | 0% (0) |
| 2000-01 | 256 | 17 | 15.1:1 | 1% (3) |
Source: NCES Common Core of Data. Rows are the federal collections on file for South Mountain School.
Since 2017-18: students down 13% (318 to 278); teachers up 8% (26.7 to 28.8).
About South Mountain School
South Mountain School is a small elementary school that serves part of MILLBURN, New Jersey. The school covers pre-K through 4 and reported 278 students in 2024-25. That puts enrollment 31% below the 405-student average for elementary schools in New Jersey.
South Mountain School sits within Millburn Township School District, which has 8 schools and 4,538 students.
At South Mountain School, 55% of students are Asian. Smaller groups are 26% White, 8% multiracial, 6% Hispanic, and 5% Black. For comparison, the population of Essex County is roughly 6% Asian. The diversity index for South Mountain School is 62%. For US public schools as a whole it is 70%.
South Mountain School reports a ratio of 9.7 students per teacher, from 28.8 full-time-equivalent teachers. The gap from the 11.4:1 average for elementary schools in New Jersey is 1.8 students per teacher. Student poverty is often measured by lunch eligibility; at South Mountain School, 3% qualify for free or reduced-price lunch. That is 51 points below the 54% average for public schools in Essex County.
South Mountain School ranks in the top 10% of New Jersey schools after adjusting test results for student poverty. Actual: 85.4%. Predicted: 64.6%. Difference: 20.8 points.
The school is in Essex County, where the median household earns about $80,789 a year, a bachelor's degree or higher is held by about 39% of adults, and the share of residents below the poverty line is 11%. South Mountain School shares Essex County with 248 other public schools.
Straight-line distance to the nearest public school, Washington School, is about 0.6 miles. Other public schools within five miles: at least 8. The average proficiency across nearby scored schools is 59.5%; South Mountain School's is 85.4%, ranking 1st of 9.
Under the NCES locale system, South Mountain School is Suburb: Large.
Over 4 years, enrollment stayed close to where it was, going from 274 to 278.
On allk12, people connected to South Mountain School can post about athletics, class schedules, and weather closures. Current and former families are welcome to add their experience.
Essex County at a glance
View full county profilePopulation
863,002
Census ACS
Median income
$80,789
Household, ACS
Bachelor's+
39%
Adults 25+
Poverty rate
11%
Below federal line
Schools in county
249
145,473 students
Quick facts
Related schools
Other schools in Millburn Township School District
- Millburn High SchoolHigh · 1,380 students
- Millburn Middle SchoolMiddle · 1,106 students
- Hartshorn SchoolElementary · 392 students
- Washington SchoolMiddle · 363 students
- Deerfield SchoolElementary · 358 students
- Wyoming SchoolElementary · 346 students
Other schools in MILLBURN
- Millburn High SchoolHigh · 1,380 students
- Millburn Middle SchoolMiddle · 1,106 students
- Washington SchoolMiddle · 363 students
- Wyoming SchoolElementary · 346 students
Nearby schools
- Washington School0.6 mi · 363
- Wyoming School0.7 mi · 346
- Millburn Middle School0.8 mi · 1,106
- Millburn High School0.9 mi · 1,380
- Jefferson Elementary1.0 mi · 564
- James Caldwell Elementary School1.1 mi · 276
Frequently asked questions
About South Mountain SchoolHow many students attend South Mountain School?
South Mountain School enrolls approximately 278 students in grades PK-04.
Is South Mountain School an elementary, middle, or high school?
South Mountain School is an elementary school covering grades PK-04.
How many teachers does South Mountain School have?
South Mountain School employs 29 FTE teachers, for a student-to-teacher ratio of 9.7:1.
How diverse is South Mountain School?
South Mountain School reports a student body of 26% White, 6% Hispanic, 5% Black, 55% Asian, 8% Two or more.
Who oversees South Mountain School?
South Mountain School is overseen by Millburn Township School District in Essex County.
Data sourceSchool profile facts are sourced from the NCES. Community content is posted by allk12 members.