The Coolock campus is located in the outer Bendigo suburb of Junortoun and provides education for Years 7–9.

[6] Catherine McAuley College is governed by the Institute of Sisters of Mercy of Australia and Papua New Guinea.

[4] Coolock (now St Mary's) also changed its homeroom model to a vertical housegroup system.

In 2017 the La Valla site changed its homeroom to vertical, so it could bring the Years 7, 8 and 9 together.

[7] At this time, both campuses were also renamed to reflect the history of the Mercy sisters and the college, with La Valla in Junortoun becoming Coolock, reflecting a location where Catherine McAuley undertook work,[8] and Coolock becoming St Mary's, the name of the college prior to 1983.