For the 2025 school year, there are 12 public high schools serving 6,510 students in Jefferson County, NY.
The top ranked public high schools in Jefferson County, NY are Thousand Islands High School, South Jefferson High School and Carthage Senior High School. Overall testing rank is based on a school's combined math and reading proficiency test score ranking.
Jefferson County, NY public high schools have an average math proficiency score of 61% (versus the New York public high school average of 55%), and reading proficiency score of 59% (versus the 59% statewide average). High schools in Jefferson County have an average ranking of 7/10, which is in the top 50% of New York public high schools.
Jefferson County, NY public high school have a Graduation Rate of 86%, which is less than the New York average of 89%.
The school with highest graduation rate is South Jefferson High School, with ≥95% graduation rate. Read more about public school graduation rate statistics in New York or national school graduation rate statistics.
Minority enrollment is 17% of the student body (majority Hispanic), which is less than the New York public high school average of 61% (majority Hispanic).
Best Public High Schools in Jefferson County (2025)
School
(Math and Reading Proficiency)
(Math and Reading Proficiency)
Location
Grades
Students
Rank: #11.
Thousand Islands High School
(Math: ≥80% | Reading: ≥80%)
Rank:
Rank:
10/
Top 10%10
8481 County Rt 9
Clayton, NY 13624
(315) 686-5594
Clayton, NY 13624
(315) 686-5594
Grades: 9-12
| 253 students
Rank: #22.
South Jefferson High School
(Math: 70-79% | Reading: 85-89%)
Rank:
Rank:
10/
Top 10%10
11060 Us Rt 11
Adams, NY 13605
(315) 232-4531
Adams, NY 13605
(315) 232-4531
Grades: 9-12
| 589 students
Rank: #33.
Carthage Senior High School
(Math: 60-69% | Reading: 85-89%)
Rank:
Rank:
9/
Top 20%10
36500 Nys Rt 26
Carthage, NY 13619
(315) 493-5030
Carthage, NY 13619
(315) 493-5030
Grades: 9-12
| 845 students
Rank: #44.
Watertown Senior High School
(Math: 55-59% | Reading: 80-89%)
Rank:
Rank:
9/
Top 20%10
1335 Washington St
Watertown, NY 13601
(315) 785-3800
Watertown, NY 13601
(315) 785-3800
Grades: 9-12
| 1,139 students
Rank: #55.
General Brown Junior-senior High School
(Math: 75-79% | Reading: 55%)
Rank:
Rank:
8/
Top 30%10
17643 Cemetery Rd
Dexter, NY 13634
(315) 779-2300
Dexter, NY 13634
(315) 779-2300
Grades: 7-12
| 654 students
Rank: #66.
Indian River High School
(Math: 70-74% | Reading: ≥50%)
Rank:
Rank:
8/
Top 30%10
32925 Us Rt 11
Philadelphia, NY 13673
(315) 642-3427
Philadelphia, NY 13673
(315) 642-3427
Grades: 9-12
| 795 students
Rank: #77.
Alexandria Central High School
(Math: 50-54% | Reading: 65-69%)
Rank:
Rank:
7/
Top 50%10
34 Bolton Ave
Alexandria Bay, NY 13607
(315) 482-5113
Alexandria Bay, NY 13607
(315) 482-5113
Grades: 7-12
| 224 students
Rank: #88.
La Fargeville Central School
(Math: 60% | Reading: 57%)
Rank:
Rank:
7/
Top 50%10
20414 Sunrise Ave
La Fargeville, NY 13656
(315) 658-2241
La Fargeville, NY 13656
(315) 658-2241
Grades: PK-12
| 465 students
Rank: #99.
Sackets Harbor Central School
(Math: 66% | Reading: 50-54%)
Rank:
Rank:
7/
Top 50%10
215 S Broad St
Sackets Harbor, NY 13685
(315) 646-3575
Sackets Harbor, NY 13685
(315) 646-3575
Grades: PK-12
| 399 students
Rank: #1010.
Lyme Central School
(Math: 50-54% | Reading: 50-54%)
Rank:
Rank:
6/
Top 50%10
11868 Academy St
Chaumont, NY 13622
(315) 649-2417
Chaumont, NY 13622
(315) 649-2417
Grades: PK-12
| 345 students
Rank: #1111.
Belleville Henderson Central School
(Math: 43% | Reading: 44%)
Rank:
Rank:
5/
Bottom 50%10
8372 County Rt 75
Adams, NY 13605
(315) 846-5121
Adams, NY 13605
(315) 846-5121
Grades: PK-12
| 503 students
Rank: n/an/a
Jefferson-lewis-hamilton-herkimer-oneida Boces
Special Education School
20104 State Rte 3
Watertown, NY 13601
(315) 779-7010
Watertown, NY 13601
(315) 779-7010
Grades: K-12
| 299 students
Jefferson County Public Schools (Closed)
School
Location
Grades
Students
Cape Vincent Correction Facility (Closed 2008)
Alternative School
Rt 12e Box 599
Cape Vincent, NY 13618
(315) 654-4100
Cape Vincent, NY 13618
(315) 654-4100
Grades: Inquire with school
| 2 students
6 Institute St
Adams, NY 13605
(315) 232-4841
Adams, NY 13605
(315) 232-4841
Grades: K-6
| 216 students
Jefferson County Jail (Closed 2004)
Alternative School
311 N Massey St
Watertown, NY 13601
Watertown, NY 13601
Grades: n/a
| n/a students
Watertown Correctional Facility (Closed 2008)
Alternative School
Dry Hl
Watertown, NY 13601
(315) 782-7490
Watertown, NY 13601
(315) 782-7490
Grades: Inquire with school
| n/a students
Frequently Asked Questions
What are the top ranked public high schools in Jefferson County, NY?
The top ranked public high schools in Jefferson County, NY include Thousand Islands High School, South Jefferson High School and Carthage Senior High School.
How many public high schools are located in Jefferson County?
12 public high schools are located in Jefferson County.
What is the racial composition of students in Jefferson County?
Jefferson County public high schools minority enrollment is 17% of the student body (majority Hispanic), which is less than the New York public high schools average of 61% (majority Hispanic).
Which public high schools in Jefferson County are often viewed compared to one another?
Popular comparisons of public high schools in Jefferson County include: Indian River High School vs. Carthage Senior High School, Carthage Senior High School vs. Indian River High School, Watertown Senior High School vs. Carthage Senior High School
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