In 1958, Brigadier Hamilton Gault left his property on Mont St. Hilaire to the University.
The bequest specified (about the mont St. Hilaire):
"...that its beauties and amenities may be preserved for all time to come, not only to the immediate interests of the university itself, but through its corridors of learning, as a great heritage for the benefit and enjoyment of the youth of Canada."
McGill University and Mont St. Hilaire
From 1958-1968, following the recommendations of the Hare Report, the Gault Estate was used for teaching and research by various departments of the University and also continued to provide recreational opportunities to local residents and the general public.
In 1960, the mountain was designated a migratory bird refuge protected under federal statutes.
In 1970, the University commissioned the Audubon Society to prepare a detailed report on the management of the mountain. The principal recommendation was that a non-profit organization be created to facilitate protection of the mountain from abuses associated with inappropriate use by visitors.
In 1972, Alice Johannsen, the University's director of what was then called the Gault Estate, acted on this recommendation and founded the Mont St. Hilaire Nature Conservation Centre. The Nature Centre is a non-profit organization entirely separate from the university. It is dedicated to the conservation of the mountain and to public education in the area of conservation and ecology.
In 1977, the University council overseeing the Gault Estate made a master plan for management of the property that recognized two primary vocations for the use of the property: 1) University teaching and research and 2) nature education for the general public.
In 1978, the Gault Estate and its immediate surroundings were designated the first Canadian Biosphere Reserve in UNESCO's Man and the Biosphere Program.
In 1995, the distinct and complementary roles of the University and the Nature Centre in the management of the Gault Estate became more clear and began to be formalized.
In 2000, the Gault Estate was officially renamed the Gault Nature Reserve by the university to better reflect the conservation mission that organized its management.
In 2004, the Gault Nature Reserve was officially recongnized as a Natural private reserve under the natural heritage conservation act by the Ministère du Développement durable, de l'Environnement et des Parcs du Québec.