WILLIAM SIDNEY MOUNT ELEMENTARY SCHOOL
Public
Elementary Grades PK–6
Part of THREE VILLAGE CENTRAL SCHOOL DISTRICT
50 DEAN LN, STONY BROOK, NY 11790 · (631) 730-4300
Community ratings
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Academic performance
Math proficiency67%
State average 56.1%
Reading / language arts67%
State average 62.6%
EDFacts via Urban Institute Education Data Portal (SY2020-21)
At a glance
525Students enrolled
13:1Student–teacher ratio
20%Free / reduced lunch
SuburbSetting
Regular SchoolSchool type
Enrollment by grade
Pre-K39
Kindergarten61
Grade 161
Grade 261
Grade 374
Grade 481
Grade 575
Grade 673
Students
White · 55%289
Asian · 24%128
Hispanic · 14%74
Two or more races · 5%28
Black · 1%6
Counts as reported to NCES; percentages are of students with a reported race/ethnicity.
Enrollment · last 5 years
455’20
470’21
511’22
514’23
525’24
Location
50 DEAN LN STONY BROOK
Neighbor reviews
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School facts from the U.S. Department of Education (NCES), 2024-2025 school year. Academic scores from the EDFacts via Urban Institute Education Data Portal (SY2020-21). Community ratings and reviews reflect neighbor opinions, not an official measure of school quality.