Largest Schools in CDSB of Eastern Ontario (2025)

Schools with the highest enrolment. Ranked by the Success Index (Canada) from official Canadian data; 45 schools in CDSB of Eastern Ontario, Ontario. Rank positions shown on each profile are within Canada and Ontario.

1
36
St Joseph's Secondary SchoolCornwall · Catholic SecondaryEnrolment: 745
2
52
St. Mother Teresa Catholic SchoolRussell · Catholic ElementaryEnrolment: 560
3
64
Notre Dame Catholic High SchoolCarleton Place · Catholic SecondaryEnrolment: 555
4
18
Holy Trinity Catholic Secondary SchoolSouth Glengarry · Catholic SecondaryEnrolment: 535
5
77
Holy Cross SchoolKemptville · Catholic ElementaryEnrolment: 530
6
80
St Michael High SchoolKemptville · Catholic SecondaryEnrolment: 520
7
73
St. Thomas Aquinas Catholic High SchoolRussell · Catholic SecondaryEnrolment: 515
8
59
St. Gregory Catholic SchoolCarleton Place · Catholic ElementaryEnrolment: 455
9
6
Sacred Heart SchoolCornwall · Catholic ElementaryEnrolment: 450
10
33
St Francis de Sales Separate SchoolSmiths Falls · Catholic ElementaryEnrolment: 430
11
58
St Mary's High SchoolBrockville · Catholic SecondaryEnrolment: 385
12
4
Bishop Macdonell Separate SchoolCornwall · Catholic ElementaryEnrolment: 385
13
70
Holy Name of Mary Separate SchoolAlmonte · Catholic ElementaryEnrolment: 375
14
34
St John Elementary SchoolPerth · Catholic ElementaryEnrolment: 375
15
46
St. Mark Catholic SchoolPrescott · Catholic ElementaryEnrolment: 350
16
39
St John Catholic High SchoolPerth Road · Catholic SecondaryEnrolment: 340
17
42
St Patrick Catholic Elementary SchoolRockland · Catholic ElementaryEnrolment: 335
18
72
St Joseph's Separate SchoolGananoque · Catholic ElementaryEnrolment: 290
19
38
St Mary's Separate SchoolCarleton Place · Catholic ElementaryEnrolment: 290
20
19
St Jude's Catholic Elementary SchoolVankleek Hill · Catholic ElementaryEnrolment: 285
21
59
St. Joseph Intermediate Catholic SchoolCornwall · Catholic ElementaryEnrolment: 275
22
52
St Peter's SchoolCornwall · Catholic ElementaryEnrolment: 265
23
62
St John Bosco Catholic SchoolBrockville · Catholic ElementaryEnrolment: 260
24
54
St Francis Xavier Catholic High SchoolHammond · Catholic SecondaryEnrolment: 260
25
53
St Anne's SchoolCornwall · Catholic ElementaryEnrolment: 260
26
53
Our Lady of Good Counsel Separate SchoolIngleside · Catholic ElementaryEnrolment: 250
27
41
St Mary-St Cecilia Catholic SchoolMorrisburg · Catholic ElementaryEnrolment: 245
28
65
Notre Dame Catholic Separate SchoolCarleton Place · Catholic ElementaryEnrolment: 230
29
44
St. John Paul II Catholic SchoolHammond · Catholic ElementaryEnrolment: 230
30
11
Holy Trinity Catholic Elementary SchoolSouth Glengarry · Catholic ElementaryEnrolment: 230
31
87
St. Thomas Aquinas Catholic SchoolRussell · Catholic ElementaryEnrolment: 225
32
60
Iona AcademyWilliamstown · Catholic ElementaryEnrolment: 225
33
42
St Joseph's Separate SchoolToledo · Catholic ElementaryEnrolment: 215
34
41
St Mary's Separate SchoolChesterville · Catholic ElementaryEnrolment: 215
35
76
St Michael Elementary SchoolKemptville · Catholic ElementaryEnrolment: 205
36
58
St Andrew's Separate SchoolSt. Andrew's West · Catholic ElementaryEnrolment: 205
37
38
St Mary's Separate SchoolBrockville · Catholic ElementaryEnrolment: 175
38
76
St. John Intermediate SchoolPerth · Catholic ElementaryEnrolment: 150
39
56
J L Jordan Separate SchoolBrockville · Catholic ElementaryEnrolment: 150
40
87
St Francis Xavier Elementary SchoolHammond · Catholic ElementaryEnrolment: 145
41
58
St Finnan's Catholic SchoolAlexandria · Catholic ElementaryEnrolment: 125
42
20
St. Luke Catholic High SchoolSmiths Falls · Catholic SecondaryEnrolment: 110
43
77
St Edward's SchoolWestport · Catholic ElementaryEnrolment: 85
44
11
St Francis Xavier Separate SchoolBrockville · Catholic ElementaryEnrolment: 80
45
64
Sacred Heart of Jesus Separate SchoolLanark · Catholic ElementaryEnrolment: 70

#	School	Sector	Enrolment	Success Index (Canada)	Key result	Students
1	St Joseph's Secondary School Cornwall · Secondary · Grades 9-12	Catholic	745	35.7 Lower 50%	83% OSSLT pass rate	745
2	St. Mother Teresa Catholic School Russell · Elementary · Grades JK-6	Catholic	560	51.5 Top 50%	72.3% EQAO Grade 6	560
3	Notre Dame Catholic High School Carleton Place · Secondary · Grades 9-12	Catholic	555	63.9 Top 50%	94% OSSLT pass rate	555
4	Holy Trinity Catholic Secondary School South Glengarry · Secondary · Grades 9-12	Catholic	535	18.2 Lower 50%	72% OSSLT pass rate	535
5	Holy Cross School Kemptville · Elementary · Grades JK-6	Catholic	530	76.5 Top 25%	81.7% EQAO Grade 6	530
6	St Michael High School Kemptville · Secondary · Grades 9-12	Catholic	520	80.0 Top 10%	97% OSSLT pass rate	520
7	St. Thomas Aquinas Catholic High School Russell · Secondary · Grades 9-12	Catholic	515	73.0 Top 25%	88% OSSLT pass rate	515
8	St. Gregory Catholic School Carleton Place · Elementary · Grades JK-3	Catholic	455	58.9 Top 50%	69.7% EQAO Grade 3	455
9	Sacred Heart School Cornwall · Elementary · Grades JK-6	Catholic	450	6.4 Lower 50%	48% EQAO Grade 6	450
10	St Francis de Sales Separate School Smiths Falls · Elementary · Grades JK-6	Catholic	430	32.7 Lower 50%	67.7% EQAO Grade 6	430
11	St Mary's High School Brockville · Secondary · Grades 9-12	Catholic	385	58.4 Top 50%	93% OSSLT pass rate	385
12	Bishop Macdonell Separate School Cornwall · Elementary · Grades JK-6	Catholic	385	4.3 Lower 50%	46% EQAO Grade 6	385
13	Holy Name of Mary Separate School Almonte · Elementary · Grades JK-8	Catholic	375	69.6 Top 25%	79.7% EQAO Grade 6	375
14	St John Elementary School Perth · Elementary · Grades JK-6	Catholic	375	34.1 Lower 50%	59% EQAO Grade 6	375
15	St. Mark Catholic School Prescott · Elementary · Grades JK-8	Catholic	350	45.8 Lower 50%	69% EQAO Grade 6	350
16	St John Catholic High School Perth Road · Secondary · Grades 9-12	Catholic	340	39.4 Lower 50%	81% OSSLT pass rate	340
17	St Patrick Catholic Elementary School Rockland · Elementary · Grades JK-6	Catholic	335	42.1 Lower 50%	65.3% EQAO Grade 6	335
18	St Joseph's Separate School Gananoque · Elementary · Grades JK-8	Catholic	290	72.3 Top 25%	84.3% EQAO Grade 6	290
19	St Mary's Separate School Carleton Place · Elementary · Grades 4-8	Catholic	290	38.0 Lower 50%	61% EQAO Grade 6	290
20	St Jude's Catholic Elementary School Vankleek Hill · Elementary · Grades JK-8	Catholic	285	19.4 Lower 50%	43.7% EQAO Grade 6	285
21	St. Joseph Intermediate Catholic School Cornwall · Elementary · Grades 7-8	Catholic	275	59.2 Top 50%	275 Enrolment	275
22	St Peter's School Cornwall · Elementary · Grades JK-6	Catholic	265	52.1 Top 50%	78% EQAO Grade 6	265
23	St John Bosco Catholic School Brockville · Elementary · Grades JK-6	Catholic	260	61.5 Top 50%	73.3% EQAO Grade 6	260
24	St Francis Xavier Catholic High School Hammond · Secondary · Grades 9-12	Catholic	260	54.1 Top 50%	81% OSSLT pass rate	260
25	St Anne's School Cornwall · Elementary · Grades JK-6	Catholic	260	52.6 Top 50%	69.7% EQAO Grade 6	260
26	Our Lady of Good Counsel Separate School Ingleside · Elementary · Grades JK-8	Catholic	250	53.0 Top 50%	76% EQAO Grade 6	250
27	St Mary-St Cecilia Catholic School Morrisburg · Elementary · Grades JK-8	Catholic	245	40.8 Lower 50%	65.7% EQAO Grade 6	245
28	Notre Dame Catholic Separate School Carleton Place · Elementary · Grades 7-8	Catholic	230	65.0 Top 50%	230 Enrolment	230
29	St. John Paul II Catholic School Hammond · Elementary · Grades JK-6	Catholic	230	43.8 Lower 50%	69.7% EQAO Grade 6	230
30	Holy Trinity Catholic Elementary School South Glengarry · Elementary · Grades 7-8	Catholic	230	11.1 Lower 50%	230 Enrolment	230
31	St. Thomas Aquinas Catholic School Russell · Elementary · Grades 6-8	Catholic	225	86.7 Top 5%	225 Enrolment	225
32	Iona Academy Williamstown · Elementary · Grades JK-8	Catholic	225	60.2 Top 50%	90.7% EQAO Grade 6	225
33	St Joseph's Separate School Toledo · Elementary · Grades JK-8	Catholic	215	42.1 Lower 50%	70% EQAO Grade 6	215
34	St Mary's Separate School Chesterville · Elementary · Grades JK-6	Catholic	215	40.9 Lower 50%	74% EQAO Grade 6	215
35	St Michael Elementary School Kemptville · Elementary · Grades 7-8	Catholic	205	76.3 Top 25%	205 Enrolment	205
36	St Andrew's Separate School St. Andrew's West · Elementary · Grades JK-8	Catholic	205	58.1 Top 50%	73.7% EQAO Grade 6	205
37	St Mary's Separate School Brockville · Elementary · Grades 7-8	Catholic	175	37.5 Lower 50%	175 Enrolment	175
38	St. John Intermediate School Perth · Elementary · Grades 7-8	Catholic	150	76.3 Top 25%	150 Enrolment	150
39	J L Jordan Separate School Brockville · Elementary · Grades JK-6	Catholic	150	56.3 Top 50%	82% EQAO Grade 6	150
40	St Francis Xavier Elementary School Hammond · Elementary · Grades 7-8	Catholic	145	86.7 Top 5%	145 Enrolment	145
41	St Finnan's Catholic School Alexandria · Elementary · Grades JK-8	Catholic	125	57.9 Top 50%	75% EQAO Grade 6	125
42	St. Luke Catholic High School Smiths Falls · Secondary · Grades 9-12	Catholic	110	20.1 Lower 50%	19% OSSLT pass rate	110
43	St Edward's School Westport · Elementary · Grades JK-8	Catholic	85	76.6 Top 25%	86.7% EQAO Grade 6	85
44	St Francis Xavier Separate School Brockville · Elementary · Grades JK-6	Catholic	80	11.1 Lower 50%	80 Enrolment	80
45	Sacred Heart of Jesus Separate School Lanark · Elementary · Grades JK-8	Catholic	70	63.6 Top 50%	80% EQAO Grade 6	70

St Joseph's Secondary School in Cornwall leads the 2025 list of largest schools in CDSB of Eastern Ontario with Enrolment 745. Of the 45 schools shown, 45 are catholic.

For the full picture see the wider Ontario largest schools rankings, every school on the CDSB of Eastern Ontario page, or the comparison tool to put a shortlist side by side.

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Frequently asked questions

What is the best largest school in CDSB of Eastern Ontario?

St Joseph's Secondary School in Cornwall, Ontario ranks first among largest schools in CDSB of Eastern Ontario with Enrolment 745 (Enrolment: 745).

How are largest schools in CDSB of Eastern Ontario ranked?

Schools with the highest enrolment. Only schools eligible for the Success Index (Canada) are included; the index is shown alongside for context.

Are these 2025 rankings official?

No. They are computed by Success Tutoring from official Canadian data (Ontario – School information and student demographics; BC Data Catalogue – Foundation Skills Assessment). Provinces publish different assessments, so scores are comparable within a province, not between provinces.