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William Sidney Mount Elementary School

Q: Is William Sidney Mount Elementary School a good school?

William Sidney Mount Elementary School ranks 764 th of 2445 New York elementary schools. SchoolDigger rates this school 3 stars out of 5.

Public Grades PK, KG-6

764^th

SchoolDigger Rank ?

of 2,445 New York Elementary Schools

Better than 69% of New York elementary schools

Summary

William Sidney Mount Elementary School is a public elementary school in Stony Brook, New York, serving 514 students in grades PK-6 as part of the Three Village Central School District. The school has consistently ranked in the top 25% of New York elementary schools over the past decade, with a peak ranking of 55th out of 2,366 schools in 2015-2016.

William Sidney Mount Elementary School's academic performance is generally above the state and district averages, particularly in English Language Arts (ELA) and Math. In 2024-2025, the school's proficiency rates were 71.11% in 6th grade ELA and 68.09% in 6th grade Math, compared to the state averages of 50.86% and 51.2%, respectively. The school's performance on state science assessments is also strong, with 66.67% of 5th graders proficient or better in 2024-2025, compared to the state average of 45.02%. The school has a low student-teacher ratio, ranging from 11.7 to 13.5 over the past three years, and its per-student spending is higher than the state average, ranging from $20,772 to $32,913 per student over the past four years.

Compared to the nearby schools in the Three Village Central School District, William Sidney Mount Elementary School generally performs at a similar or higher level on state assessments. The school's consistent high performance and efficient use of resources are noteworthy achievements, though the school's performance for certain subgroups, such as low socioeconomic status students, could be improved.

525

Students ?

13.0

Student/teacher ratio ?

$33,240

Per pupil spending ?

20.4%

Free/discounted lunch ?

50 Dean Ln
Stony Brook, NY 11790-2799

(631) 730-4300

District: Three Village Central School District

Students who attend William Sidney Mount Elementary School usually attend:

Middle:	Robert Cushman Murphy Junior High School
High:	Ward Melville Senior High School

Racial breakdown:

White:

55.0%

Asian:

24.4%

Hispanic:

14.1%

See top rated New York elementary schools

Compare William Sidney Mount Elementary School to nearby elementary schools!

At a glance

▼ Ranking trend: Declining — 97th percentile in 2015 → 69th in 2025

Strengths

✓Test scores above the New York average (63% vs 54% meeting standards)

✓Above the New York median (69th percentile)

Worth a look

!Ranking has slipped — down 28 percentile points since 2015

!Some student groups rank well below the school's overall statewide standing

!Near the bottom of Three Village Central School District's ranking

Students meeting standards (2024-2025) ?

This school63%

District avg71%

New York avg54%

764^th of 2,445

New York public elementary schools ?

Top 31%▼ down 28 pts since 2015

From top 3% (2015) to top 31% (2025)

See the entire ranking list of New York Elementary Schools →

★★★★★

SchoolDigger rating ?

4^th of 5Elementary Schools in the Three Village Central School District

157^th of 874Three Village Central School District among New York districts

Statewide rank percentile over time (100 = the top-ranked school in the state; click a legend item to add a student group)

Show full rank history (all student groups)

All Students

Year	Avg score	Statewide rank	New York percentile	Rating
2025	67.0	764 of 2445	68.8%	★★★☆☆
2024	70.3	632 of 2445	74.2%	★★★★☆
2023	74.7	574 of 2439	76.5%	★★★★☆
2022	76.1	511 of 2434	79.0%	★★★★☆
2021	74.2	503 of 2201	77.1%	★★★★☆
2019	83.7	343 of 2413	85.8%	★★★★☆
2018	84.5	278 of 2395	88.4%	★★★★☆
2017	84.6	276 of 2386	88.4%	★★★★☆
2016	94.2	55 of 2366	97.7%	★★★★★
2015	93.4	69 of 2352	97.1%	★★★★★
2014	88.4	177 of 2345	92.5%	★★★★★
2013	89.8	159 of 2325	93.2%	★★★★★
2012	83.9	259 of 2320	88.8%	★★★★☆
2011	86.3	185 of 2286	91.9%	★★★★★
2010	83.5	233 of 2263	89.7%	★★★★☆
2009	81.9	181 of 2257	92.0%	★★★★★
2008	83.3	172 of 2227	92.3%	★★★★★
2007	84.1	167 of 2219	92.5%	★★★★★
2006	86.3	81 of 2206	96.3%	★★★★★

Asian

Year	Avg score	Statewide rank	New York percentile	Rating
2025	52.2	379 of 696	45.5%	★★☆☆☆
2024	62.7	259 of 662	60.9%	★★★☆☆
2023	53.0	329 of 605	45.6%	★★☆☆☆
2022	63.3	278 of 671	58.6%	★★★☆☆
2021	54.6	234 of 430	45.6%	★★☆☆☆
2019	73.2	129 of 548	76.5%	★★★★☆
2018	62.1	253 of 601	57.9%	★★★☆☆

English Language Learner

Year	Avg score	Statewide rank	New York percentile	Rating
2025	52.9	406 of 1117	63.7%	★★★☆☆
2024	55.3	314 of 1066	70.5%	★★★★☆
2023	45.2	466 of 1001	53.4%	★★★☆☆
2022	53.2	346 of 1027	66.3%	★★★☆☆
2021	58.7	135 of 454	70.3%	★★★★☆

Female

Year	Avg score	Statewide rank	New York percentile	Rating
2025	67.7	716 of 2409	70.3%	★★★★☆
2024	69.8	615 of 2413	74.5%	★★★★☆
2023	75.3	528 of 2403	78.0%	★★★★☆
2022	68.4	675 of 2401	71.9%	★★★★☆
2021	72.8	446 of 1955	77.2%	★★★★☆
2019	80.2	390 of 2357	83.5%	★★★★☆
2018	82.1	313 of 2338	86.6%	★★★★☆

Low Socio Economic Status

Year	Avg score	Statewide rank	New York percentile	Rating
2025	27.7	1599 of 2098	23.8%	★☆☆☆☆
2024	34.0	1379 of 2078	33.6%	★★☆☆☆
2023	48.7	929 of 2041	54.5%	★★★☆☆
2022	57.8	729 of 2099	65.3%	★★★☆☆
2021	59.0	584 of 1678	65.2%	★★★☆☆
2019	67.6	502 of 2032	75.3%	★★★★☆

Male

Year	Avg score	Statewide rank	New York percentile	Rating
2025	64.3	804 of 2407	66.6%	★★★☆☆
2024	67.0	706 of 2411	70.7%	★★★★☆
2023	69.0	676 of 2400	71.8%	★★★★☆
2022	77.1	451 of 2400	81.2%	★★★★☆
2021	67.7	578 of 1961	70.5%	★★★★☆
2019	83.8	304 of 2358	87.1%	★★★★☆
2018	80.7	347 of 2340	85.2%	★★★★☆

Special Education

Year	Avg score	Statewide rank	New York percentile	Rating
2018	70.8	310 of 1941	84.0%	★★★★☆

White

Year	Avg score	Statewide rank	New York percentile	Rating
2025	50.2	751 of 1402	46.4%	★★☆☆☆
2024	50.3	689 of 1392	50.5%	★★★☆☆
2023	62.3	508 of 1337	62.0%	★★★☆☆
2022	58.4	567 of 1399	59.5%	★★★☆☆
2021	70.8	337 of 1224	72.5%	★★★★☆
2019	72.3	365 of 1338	72.7%	★★★★☆
2018	74.7	294 of 1408	79.1%	★★★★☆

How student groups rank statewide ? (each group's percentile vs the same group at other schools — higher is better; the +/- beside each compares the group with this school's overall percentile)

Special Education (2018)84th percentile-4 vs school

Female (2025)70th percentile~ school

Male (2025)67th percentile~ school

English Language Learner (2025)64th percentile-5 vs school

White (2025)46th percentile-22 vs school

Asian (2025)46th percentile-23 vs school

Low Socio Economic Status (2025)24th percentile-45 vs school

By subject vs New York (2024-2025) ?

Math67%+11 vs state

Science67%+22 vs state

English Language Arts59%+5 vs state

★

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Schools Near William Sidney Mount Elementary School

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Ranking:

E Elementary M Middle H High A Alternative P Private

Choose columns to see: Summary School Students/Teachers Ranking Test Scores Immunizations Finance All

School													Students/Teachers											Ranking (2025)				Ranking (2024)				NY State Assessments English Language Arts (2025)				NY State Assessments Math (2025)				NY State Assessments Science (2025)	% Completely Immunized (2020)	% Polio (2020)	% Measles (2020)	% Mumps (2020)	% Rubella (2020)	% Diphtheria (2020)	% Hepatitis B (2020)	% Varicella (2020)	Per Pupil Expenditures (2025)
Name	Type	Grades	Address	City	Zip	County	District	Is Charter	Is Magnet	Is Virtual	Is Title I	Phone	Enrollment	Full-time Teachers	Student/ Teacher Ratio	Free/Discounted Lunch Recipients	White	Black	Hispanic	Asian	American Indian	Pacific Islander	Two or More Races	Average Standard Score (2025)	Statewide Rank (2025)	State Percentile (2025)	SchoolDigger Rating (2025)	Average Standard Score (2024)	Statewide Rank (2024)	State Percentile (2024)	Rank Change from Previous Year	NY State Assessments English Language Arts 3rd Grade	NY State Assessments English Language Arts 4th Grade	NY State Assessments English Language Arts 5th Grade	NY State Assessments English Language Arts 6th Grade	NY State Assessments Math 3rd Grade	NY State Assessments Math 4th Grade	NY State Assessments Math 5th Grade	NY State Assessments Math 6th Grade	NY State Assessments Science 5th Grade	% Completely Immunized All Grades	% Polio All Grades	% Measles All Grades	% Mumps All Grades	% Rubella All Grades	% Diphtheria All Grades	% Hepatitis B All Grades	% Varicella All Grades	Per Pupil Expenditures Total	Sub-total from Federal Funds	Sub-total from State/Local Funds
William Sidney Mount Elementary School	Public	PK, KG-6	50 Dean Ln	Stony Brook	11790	Suffolk County	Three Village Central School District	No	No	No	No	(631) 730-4300	525	40	13.0	20.4%	289 (55.0%)	6 (1.1%)	74 (14.1%)	128 (24.4%)	0 (0.0%)	0 (0.0%)	28 (5.3%)	67	764^th of 2445 public elementary schools	68.8%		70.3	632^nd of 2445 public elementary schools	74.2%	132	54.2	47.1	66.0	71.1	65.6	68.0	66.1	68.1	66.7	97.8	98.2	100.0	100.0	100.0	98.6	99.8	99.4	$33,240	$624	$32,616
Mills Pond Elementary School	Public	K-5	246 Moriches Rd	Saint James	11780	Suffolk County	Smithtown Central School District	No	No	No	No	(631) 382-4305	338	27	12.5	17.2%	248 (73.4%)	6 (1.8%)	50 (14.8%)	22 (6.5%)	0 (0.0%)	1 (0.3%)	11 (3.3%)	79.9	429^th of 2445 public elementary schools	82.5%		70.7	618^th of 2445 public elementary schools	74.7%	189	63.0	72.0	90.0		62.5	73.1	79.6		78.4	98.5	99.0	99.8	99.8	99.8	99.3	99.0	99.5	$36,583	$356	$36,226
Saint James Elementary School	Public, Magnet	K-5	580 Lake Ave	Saint James	11780	Suffolk County	Smithtown Central School District	No	Yes	No	No	(631) 382-4455	461	38	12.2	22.3%	348 (75.5%)	3 (0.7%)	73 (15.8%)	20 (4.3%)	0 (0.0%)	0 (0.0%)	17 (3.7%)	52.7	1136^th of 2445 public elementary schools	53.5%		62.8	828^th of 2445 public elementary schools	66.1%	308	51.5	58.3	65.9		42.4	72.0	60.0		48.8	99.0	99.2	99.8	99.8	99.8	99.2	99.8	99.4	$35,378	$102	$35,276
Nassakeag Elementary School	Public	PK, KG-6	490 Pond Path	East Setauket	11733	Suffolk County	Three Village Central School District	No	No	No	No	(631) 730-4400	551	44	12.6	8.5%	323 (58.6%)	10 (1.8%)	52 (9.4%)	143 (26.0%)	0 (0.0%)	0 (0.0%)	23 (4.2%)	87.9	241^st of 2445 public elementary schools	90.1%		90.6	186^th of 2445 public elementary schools	92.4%	55	69.1	91.3	85.7	78.3	62.1	95.5	89.1	81.1	75.4	99.2	99.6	99.8	99.8	99.8	99.4	99.6	99.8	$34,438	$392	$34,046
Eugene Auer Memorial School	Public	K-5	17 Wing St	Lake Grove	11755	Suffolk County	Middle Country Central School District	No	No	No	No	(631) 285-8500	308	22	13.9	42.2%	178 (57.8%)	15 (4.9%)	79 (25.6%)	26 (8.4%)	0 (0.0%)	0 (0.0%)	10 (3.2%)	14.3	2213^th of 2445 public elementary schools	9.5%		17.9	2123^rd of 2445 public elementary schools	13.2%	90	29.4	16.7	22.2		35.3	36.0	24.0		41.7	98.5	98.9	98.9	98.9	98.9	99.3	99.3	99.3	$36,645	$923	$35,722
Minnesauke Elementary School	Public	PK, KG-6	21 Highgate Dr	East Setauket	11733	Suffolk County	Three Village Central School District	No	No	No	No	(631) 730-4200	644	54	11.9	13.8%	451 (70.0%)	11 (1.7%)	83 (12.9%)	60 (9.3%)	2 (0.3%)	0 (0.0%)	37 (5.7%)	80.1	424^th of 2445 public elementary schools	82.7%		91	178^th of 2445 public elementary schools	92.7%	246	67.7	70.3	62.7	76.3	75.0	92.3	61.9	85.1	61.9	98.6	98.8	99.7	99.7	99.7	99.0	99.1	99.5	$36,247	$541	$35,705
Oxhead Road School	Public	1-5	144 Oxhead Rd	Centereach	11720	Suffolk County	Middle Country Central School District	No	No	No	Yes	(631) 285-8700	383	22	17.8	45.7%	170 (44.4%)	13 (3.4%)	153 (39.9%)	30 (7.8%)	0 (0.0%)	0 (0.0%)	17 (4.4%)	36.7	1562^nd of 2445 public elementary schools	36.1%		41	1414^th of 2445 public elementary schools	42.2%	148	40.0	39.5	62.2		47.4	47.6	50.0		48.5	98.3	99.8	99.8	99.8	99.8	99.8	99.8	98.3	$29,604	$1,398	$28,207
Wenonah School	Public	K-5	251 Hudson Ave	Lake Grove	11755	Suffolk County	Sachem Central School District	No	No	No	No	(631) 471-1880	488	45	10.8	28.9%	310 (63.5%)	21 (4.3%)	114 (23.4%)	27 (5.5%)	1 (0.2%)	0 (0.0%)	15 (3.1%)	70.2	687^th of 2445 public elementary schools	71.9%		56.8	978^th of 2445 public elementary schools	60.0%	291	81.1	73.3	42.9		84.2	76.5	48.0		54.2	99.0	99.2	99.2	99.2	99.2	99.2	99.6	99.4	$30,282	$635	$29,646
Dogwood Elementary School	Public	K-5	50 Dogwood Dr	Smithtown	11787	Suffolk County	Smithtown Central School District	No	No	No	No	(631) 382-4255	350	28	12.5	13.1%	281 (80.3%)	2 (0.6%)	46 (13.1%)	11 (3.1%)	1 (0.3%)	1 (0.3%)	8 (2.3%)	73.9	589^th of 2445 public elementary schools	75.9%		62.6	837^th of 2445 public elementary schools	65.8%	248	69.8	57.8	78.1		69.8	60.4	80.5		70.7	98.1	98.4	100.0	100.0	100.0	98.7	98.9	99.2	$34,275	$83	$34,192
Unity Drive Kindergarten-Pre K Center	Public	PK-K	11 Unity Dr	Centereach	11720	Suffolk County	Middle Country Central School District	No	No	No	No	(631) 285-8760	478	19	25.0	39.3%	223 (46.7%)	28 (5.9%)	154 (32.2%)	55 (11.5%)	1 (0.2%)	0 (0.0%)	17 (3.6%)								(n/a)										98.5	98.8	98.8	98.8	98.8	98.8	100.0	98.5	$31,418	$7,275	$24,143

Frequently Asked Questions about William Sidney Mount Elementary School

What district is William Sidney Mount Elementary School in?

Three Village Central School District

How many students attend William Sidney Mount Elementary School?

In the 2024-25 school year, 525 students attended William Sidney Mount Elementary School.

What schools do graduates of William Sidney Mount Elementary School attend?

Students who attend William Sidney Mount Elementary School usually go on to attend:

Middle : Robert Cushman Murphy Junior High School
High : Ward Melville Senior High School

What is the racial makeup of William Sidney Mount Elementary School?

Students at William Sidney Mount Elementary School are 55% White, 24% Asian, 14% Hispanic, 5% Two or more races, 1% African American.

Is William Sidney Mount Elementary School a good school?

William Sidney Mount Elementary School ranks 764^th of 2445 New York elementary schools. SchoolDigger rates this school 3 stars out of 5.

Rate William Sidney Mount Elementary School!

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SchoolDigger data sources: National Center for Education Statistics, U.S. Department of Education, the U.S. Census Bureau, the WNYC and the New York State Department of Health and the NY State Education Department.

IMPORTANT DISCLAIMERS: Not all boundaries are included. We make every effort to ensure that boundaries are up-to-date. But it's important to note that these are approximations and are for general informational purposes only. To verify legal descriptions of boundaries or school locations, contact your local tax assessor's office and/or school district.