Harbor Country Day School
Private · Grades Pre-K–8 · 117 students
William Sidney Mount Elementary School
50 Dean Ln, Stony Brook, NY 11790
Grades
Pre-K–6
Elementary
Students
525
Enrolled 2024–25
Students per teacher
13 : 1
Full-time teachers
District
Three Village Central School District
Suffolk County
Schola Grade B · Above average
Letter grade (A–F) · compared with 2,327 New York elementary schools · How we grade
Percentiles compare this school with other New York elementary schools; the line marks the middle. Data: test scores 2021–22, graduation and absenteeism 2022–23 (U.S. Department of Education, EDFacts); coursework 2023–24 (Civil Rights Data Collection); staffing 2024–25 (NCES).
About William Sidney Mount Elementary School
William Sidney Mount Elementary School is a public elementary school in Stony Brook, New York, serving grades Pre-K–6. It is part of Three Village Central School District. The school is located in a large suburb in Suffolk County.
In the 2024–25 school year, 525 students were enrolled, with about 13 students for every full-time teacher. That ratio is larger than the typical New York elementary school (11.5 students per teacher). Its Schola Grade is B (above average), compared with 2,327 New York elementary schools.
Grades & enrollment
Students per grade, 2024–25Grades Pre-K–6
Location & nearby schools
School details
- Type
- Public School · What this means
- Level
- Elementary
- Grades offered
- Pre-K–6
- Enrollment (2024–25)
- 525 students
- Students per teacher
- 13 to 1
- Charter school
- No
- Magnet school
- No
- Locale
- Suburb — Large
- School district
- Three Village Central School District
- County
- Suffolk County
- NCES school ID
- 362820003810
Schools near William Sidney Mount Elementary School
All 4 schools in Stony Brook →
Mills Pond Elementary School
Public · Grades K–5 · 338 students
Montessori School at Old Field
Private · Grades Pre-K–3 · 4 students
Saint James Elementary School
Public · Grades K–5 · 461 students
Ss Philip & James School
Private · Grades Pre-K–8 · 126 students
Nassakeag Elementary School
Public · Grades Pre-K–6 · 551 students
School data comes from the U.S. Department of Education: the National Center for Education Statistics (NCES) Common Core of Data and EDGE school locations (2024–25) and Private School Survey (2023–24), the Civil Rights Data Collection (2023–24), and EDFacts (test results 2021–22; graduation and chronic absenteeism 2022–23), plus other public sources. Please contact the school to confirm enrollment, programs, and other details. How we source data.