At the request of Laurence Sheil, then the Bishop of Adelaide, St Mary's College was founded by the Dominican Sisters who arrived from the Dominican Convent in Cabra, Ireland as missionaries. The foundation stone was laid in 1868. The Sisters of St Joseph of the Sacred Heart provided primary education for students from the lower socioeconomic status while the Dominican Sisters took responsibility for middle-class girls from both Catholic and other religious backgrounds whose parents could afford post-primary education.
Academics
Approximately 800 girls attend the school in classes from Reception to year 12. The school offers a "Year 13" program for students who wish to obtain their Stage 2 SACE over two years.
Houses
The school has four sporting houses, in which the students are placed at the commencement of their enrolment at St Mary's. St Marys, St Dominics, St Catherines and St Thomas each compete in annual sports days and swimming carnivals.
Extracurricular activities
St Mary's supports many charities and selects Year 11 students to attend pilgrimages annually. One is called the "Lands Trip", led by Robert Napoli, Learning Area Co-Ordinator for Religious Education. The Lands Trip selects 6 - 8 girls to travel into the APY Lands, to visit an Aboriginal community and experience the literacy of some Indigenous Australians. This pilgrimage started in 2008 and is renowned for being tough on the emotions and physical abilities of the students embarking this trip. The other pilgrimage is to Vietnam. In 2005, 2006, 2007 and 2008 St Mary's College and Christian Brothers College students' combined to participate in a Pilgrimage to Vietnam. The primary focus of the Pilgrimage is on giving service and working with orphaned, disabled children in the Phu My Orphanage in the Thi Nghe District, Saigon. The Orphanage is operated by the Sisters of St Paul de Charters where they provide care for over 300 children. While at the Orphanage students participate in a range of activities and are immersed in the day-to-day operation of the Orphanage.
Campus
The campus also contains:
Four buildings containing classroom, computer, science, art and home economic facilities. The historical Boylan building, the Moore Building, the Catherine and Kavanagh buildings
The school also shares campus with St Patricks Catholic Church and resides next to the Archbishops House on West Terrace. The school borders three streets. The front facing Franklin Street, the West Side fencing West Terrace, the back facing Grote Street and fences side street, Gray Street.
