The Patron Saint of the school is known for being the Mother of Jesus.
This school's name honours the prominent place of Mary in our Catholic faith.
The school was founded in 1984 and has been located at its current site since September 1998.

Did you know that St. Mary...

  • was established in 1998 and is located adjacent to a wooded property along Birchwood Trail in Cobourg about 120 km East of Toronto, in Central Ontario, Canada. St. Mary Catholic Secondary School has been part of the Cobourg community in Northumberland County for over 35 years.

  • is the only Catholic Secondary School in Northumberland County.

  • is a fully accessible building including 2 elevators.

  • is a uniform school.

  • prides itself on a high selection of extra-curricular activities including over 50 clubs and sports teams.

  • offers a French Immersion Program, six Specialist High Skills Major Programs, and offers Dual credits (1 college + 1 high school credit) in partnership with Fleming, Durham and Loyalist Colleges.

  • has a Centre for Autism Spectrum Assistance (CASA) room. CASA provides an alternate classroom placement for which students identified Communications: Autism. These students can learn and practice alternate skills and strategies that will allow them to manage successfully in their homeschool setting located in the school.

  • provides a Board Chromebook to every student to use for the duration of their schooling at St. Mary.

  • has a Breakfast Program. Our school and community recognize the value of a breakfast for proper growth, development and functioning of students. Students arriving without a proper morning meal are encouraged to take advantage of this breakfast program. A breakfast bin is located in the front office for students to access healthy food items anytime of the day.

  • has an outdoor rubber running track and 2 fitness rooms that help optimize the performance of school athletes.

  • has specialized courses in manufacturing, construction and transportation with some of the latest technology which enables students to build a foundation of current sector-focused knowledge and skills before entering apprenticeship training, college, university, or an entry-level position in the workplace.

Regular Day Bell Schedule

    • Warning Bell: 8:10 am

    • Period 1: 8:15 - 9:30 am

    • Period 2: 9:35 - 10:50 am

    • Period 3: (Gr. 9 & 10) 10:55 am - 12:10 pm

    • Lunch A: (Gr. 11 & 12) 10:50 - 11:30 am

    • Lunch B: (Gr. 9 & 10) 12:10 - 12:50 pm

    • Period 4: (Gr. 11 & 12) 11:30 am - 12:45 pm

    • Period 5: 12:50 - 2:05 pm


St. Mary Catholic Secondary School operates on a 2 semester system.

Semester 1: September to January
Semester 2: February to June

Social Feeds


Main School: @SMCSSThunder

Jack Chapter:
Student Council:


Parents/guardians are asked to call the school to report your son/daughter’s absences. Messages can be left at extension 267, 24 hours day. Parents/guardians will be contacted each evening by an automated dialer if an unexplained absence from one or more classes occurred during that school day. Detailed information on attendance procedures can be found in the student agenda. A quick reference magnet is available.

Religious Education and Ceremonies

To ensure the integrity of our ministry of Catholic Education, St. Mary Catholic Secondary School students undertake a religious education course during each year of study and they participate in religious celebrations. This provides our students with the opportunity to learn about and celebrate their faith. It is understood that registration and attendance at this school is founded upon these components of Catholic Education.

We look forward to sharing our ministry of Catholic Education with your child and family.

Lunch Options

Students at St. Mary can purchase breakfast and lunch items from our cafeteria. Students always have a wide selection of food items to choose from. They can either eat in the cafeteria or enjoy the picnic tables outside on the patio weather permitting. Students also have the option of walking to several nearby food establishments.

Students are reminded that food must be eaten in the cafeteria and not in the halls or classrooms.

School Fees

What is School Cash Online?

The Peterborough Victoria Northumberland and Clarington Catholic District School Board is pleased to offer School Cash Online, a secure payment option that allows parents to purchase items and pay for student fees online 24/7 from the comfort of their home.

What is School Cash Online?

School Cash Online is an easy to use, safe way to pay for your children’s school fees. All you have to do is register an account, attach your children and in no time you will be able to make payments online.

Specialized Programs

Specialist High Skills Majors let students focus on a career path that matches their skills and interests while meeting the requirements of the Ontario Secondary School Diploma (OSSD)

SHSM programs offered at St. Mary:

Arts & Culture
Information and Communication Technology
Sports Excellence and Athletic Leadership