Robert M Grable Jr Mount Sinai High School, Mount Sinai NY

Original Research by School Decision on Robert M Grable Jr Mount Sinai High School

Robert M. Grable Jr. Mount Sinai High School is a regular public high school serving grades nine through twelve in a small residential North Shore hamlet on Long Island. The school enrolls roughly seven hundred students, with a racial composition that is predominantly white, alongside a meaningful share of Hispanic and Asian students, and a small share of Black students. About one in nine students qualifies for free or reduced-price lunch, indicating modest economic diversity within a fairly affluent community.

Mount Sinai is an overwhelmingly residential hamlet without a traditional downtown, built from single-detached homes on tree-lined streets near Long Island Sound. It has grown from a tiny agricultural village through postwar suburbanization and recent planned residential subdivisions. Commercial life concentrates along Route 25A near a King Kullen supermarket center; for walkable dining and shopping, residents travel to nearby Port Jefferson. The school sits on a consolidated three-school campus at the northern edge of the hamlet, separate from the commercial strip. Housing values in the area are substantial, reflecting the Long Island market. Families choosing this district are selecting a quiet, family-oriented suburb with strong civic participation centered on schools, parks, and the harbor rather than a downtown core.

The district has recently undergone two significant shifts. In September 2025, voters approved a bond referendum for safety upgrades, modernized learning environments, roadway and parking reconstruction, and a new athletic turf field. The referendum carries a lasting property tax impact on homeowners, financed over roughly thirty years, making it a material consideration for families weighing a move to the district. The district is also launching a state-funded Universal Pre-Kindergarten program beginning in fall 2026, offering free, full-week preschool for eligible families, a meaningful addition for younger siblings.

The district's adopted strategic plan, Mustang Pride: Building Our Future 2030, emphasizes career pathways, dual enrollment, Advanced Placement, computer science and coding, and financial literacy alongside broader priorities in teaching, wellness, and student experience. This signals the instructional direction and program breadth families can expect over the coming years.

State testing data and graduation rates were not available for this school, so a comparative read of academic performance cannot be drawn from the provided information. A parent interested in understanding how the school's test results or completion rates compare to other Long Island high schools would want to request those metrics directly from the district or consult the New York State Department of Education's publicly reported performance data.

The school serves a community that is close-knit, organized around family and education, and engaged in long-term planning. The recent bond investment and curriculum expansions reflect a district betting on its future. For families drawn to a stable, residential Long Island setting with active civic life and school-centered community, Mount Sinai presents a clear fit, contingent on understanding the property tax and academic performance picture in full.

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Academic performance

How students graduate and prepare for what comes next.

Graduation rate (ACGR)

>=95%Cohort of 197 students · Class of 2021

The federal source publishes a banded range instead of an exact rate when the graduating cohort is small enough that an exact number could risk identifying individual students.

How this school compares to all schools in this state

Each dot is one school’s SY 2020-21 graduation rate, binned by integer rate. Taller columns mean more schools at that rate. This school is highlighted.

1,253 schools plotted. 14 additional schools' rates are federally suppressed and not shown. Data: EDFacts SY 2020-21.

Advanced Placement & IB

25 subjects offered · 2023-24

Each card is one AP or IB subject. The headline number is the share of students scoring 3 or higher on the exam — the threshold for college credit at most universities. The bar below each rate shows the underlying distribution across performance levels.

Score:12· no credit345· extremely well qualified

Math and Computer Science

Calculus AB

16 tested

87.5%

scored 3 or higher

Calculus BC

10 tested

80.0%

scored 3 or higher

Computer Science A

11 tested

72.7%

scored 3 or higher

Computer Science Principles

30 tested · Grade 9, Grade 10

76.7%

scored 3 or higher

Precalculus

1 tested

0.0%

scored 3 or higher

Statistics

18 tested · Grade 10

77.8%

scored 3 or higher

Sciences

Biology

16 tested

93.8%

scored 3 or higher

Chemistry

6 tested · Grade 10

0.0%

scored 3 or higher

Environmental Science

10 tested

60.0%

scored 3 or higher

Physics 1

24 tested

75.0%

scored 3 or higher

Physics C: Mechanics

1 tested

0.0%

scored 3 or higher

History and Social Sciences

Human Geography

2 tested

0.0%

scored 3 or higher

Psychology

28 tested

75.0%

scored 3 or higher

U.S. History

55 tested · Grade 10

78.2%

scored 3 or higher

World Languages and Cultures

French Language and Culture

2 tested

0.0%

scored 3 or higher

Italian Language and Culture

1 tested

0.0%

scored 3 or higher

Japanese Language and Culture

1 tested

0.0%

scored 3 or higher

Spanish Language and Culture

7 tested

100.0%

scored 3 or higher

Arts

Studio Art Drawing

4 tested

0.0%

scored 3 or higher

Other

Language and Comp

69 tested

63.8%

scored 3 or higher

Literature and Comp

34 tested

88.2%

scored 3 or higher

Studio Art 2d Design

3 tested

0.0%

scored 3 or higher

Studio Art 3d Design

1 tested

0.0%

scored 3 or higher

U S Government and Politics

50 tested

86.0%

scored 3 or higher

World History

52 tested · Grade 10

94.2%

scored 3 or higher

New York Regents Exams

4 courses reported · 2024-25

End-of-course exams required for a New York Regents diploma. Each row shows the cohort size and the share of students scoring at the proficient level or higher.

Course	Students tested	% proficient
Ela	171	96.0%
Social Studies	161	98.0%
Math	138	97.0%
Science	122	89.0%

Graduation rate (ACGR) reflects the federally published Adjusted Cohort Graduation Rate for the most recent year available. We refresh this data annually at the close of each academic year in June. The federal source publishes a banded rate (for example, "90-94%") instead of an exact number for cohorts small enough to risk identifying individual students. The state distribution chart, where shown, plots every school in the state with a published rate or band; schools whose rate is federally suppressed are excluded. Where the federal source publishes a band rather than an exact rate, the school is placed within its band using a stable, ID-derived offset, so its position is consistent across visits.