William Sidney Mount Elementary School
🇺🇸 Official data · 2025Stony Brook, New York 11790 · Three Village Central School District
#251 of 2,536 elementary schools in New York
#2924 of 50,301 nationally
About William Sidney Mount Elementary School
William Sidney Mount Elementary School is a public elementary located in Stony Brook, in the Three Village Central School District school district of New York, United States. It caters for Grades PK–6. In 2025 it enrolled 525 students. Traditional public schools run by a school district; free to attend.
Its Success Index (US) is 84.0 out of 100, placing it in the top 10% of elementary schools in United States and 251st of 2,536 ranked elementary schools in New York. Its strongest component is math proficiency (91th percentile), and its weakest is students per teacher (70th percentile).
Other published figures: enrollment 525.
There are 2 schools in Stony Brook; William Sidney Mount Elementary School ranks 2nd of 2 scored schools there.
Success Index (US) breakdown
Each component is a percentile against elementary schools across United States.
- Math proficiency (30%)77%
- Reading proficiency (30%)67%
- Community advantage (fewer free/reduced-price lunch) (25%)20.4%
- Students per teacher (15%)13.1
The Success Index (US) summarises published data about a school community. It is not a measure of teaching quality. Read the methodology.
Published measures
All figures published for William Sidney Mount Elementary School by the official sources.
- Enrollment
- 525
- Students enrolled in the latest NCES directory year.
- Free/reduced-price lunch
- 20.4%
- Share of students eligible for free or reduced-price lunch.
- Students per teacher
- 13.1
- Enrollment divided by FTE teachers; not class size.
- Reading proficiency
- 67%
- Share of tested students proficient or above (all students, all grades).
- Math proficiency
- 77%
- Share of tested students proficient or above (all students, all grades).
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Schools near William Sidney Mount Elementary School
Closest schools by straight-line distance, with their Success Index (US).
Robert Cushman Murphy Junior High School
Stony Brook · Public middle · Grades 7–9
655 students · 1.9 km away
Mills Pond Elementary School
ST James · Public elementary · Grades K–5
338 students · 2.0 km away
Saint James Elementary School
Saint James · Public elementary · Grades K–5
461 students · 2.2 km away
Nassakeag Elementary School
East Setauket · Public elementary · Grades PK–6
551 students · 3.2 km away
Smithtown High School East
Saint James · Public high · Grades 9–12
1,403 students · 3.6 km away
Eugene Auer Memorial School
Lake Grove · Public elementary · Grades K–5
308 students · 3.7 km away
Minnesauke Elementary School
East Setauket · Public elementary · Grades PK–6
644 students · 4.2 km away
Nesaquake Middle School
Saint James · Public middle · Grades 6–8
466 students · 4.2 km away
Oxhead Road School
Centereach · Public elementary · Grades 1–5
383 students · 4.4 km away
Dawnwood Middle School
Centereach · Public middle · Grades 6–8
967 students · 4.5 km away
Similar schools
Public elementary schools in New York with a comparable Enrollment.
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525 students
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Richmond Hill · Public elementary · Grades PK–5
525 students
Northwest Elementary School
Amityville · Public elementary · Grades K–2
525 students
School 17-Enrico Fermi
Rochester · Public elementary · Grades PK–6
525 students
Ps 130 Hernando de Soto
New York · Public elementary · Grades PK–5
526 students
Jermaine L Green STEM Institute of Queens (The)
Jamaica · Public elementary · Grades PK–5
526 students
Frequently asked questions
Is William Sidney Mount Elementary School a good school?
William Sidney Mount Elementary School has a Success Index (US) of 84.0 out of 100 (Top 10% of elementary schools in United States) and ranks #251 of 2,536 in New York. The index summarises published data about the school community and, where available, attainment; it does not measure teaching quality, so visit the school and ask about support at your child's level.
Where does William Sidney Mount Elementary School rank in New York?
William Sidney Mount Elementary School ranks #251 of 2,536 elementary schools in New York and #2924 of 50,301 nationally on the Success Index (US) (2025 data).
How many students attend William Sidney Mount Elementary School?
William Sidney Mount Elementary School had 525 students in 2025.
Is William Sidney Mount Elementary School a elementary school or a high school?
William Sidney Mount Elementary School is classified as a elementary covering Grades PK–6. It is a public school.
What other schools are near William Sidney Mount Elementary School?
There are 10 schools within 15 km of William Sidney Mount Elementary School; they are listed on this page with their Success Index (US) and distance, and can be compared side by side.