Site plan of the point showing the site of the convent, as projected by surveyor Henri-Maurice Perrault

In 1784, the number of parishioners in Pointe-Claire was 800, including those of Bout-de-l'Ile, while Lachine’s parishioners had decreased to no more than 300. The Congregation of Notre Dame, whose convent was falling into ruin, decided to move from Lachine to Pointe-Claire. Their first building was built in 1787, behind the cemetery located between the presbytery and the existing church.

In the 19th century, the project to build a more imposing church motivated the fabrique to propose a land exchange with the congregation, and the point was acquired with this intention. The present convent was built in 1867-1868 by Octave and Louis Bourgouin, according to plans by Henri-Maurice Perrault. It is a single building made of uncut stone, with a basement, ground floor, upper floor and attic. The ridge roof with dormer windows had a pinnacle turret in the centre.

In 1962, approximately 100 years later, the structure was enlarged by adding two perpendicular wings to the older main building. These were designed by architect Louis-Napoléon Audet. He proposed using the same materials and architectural style as were employed in the original building. The original cornice with modillions of the ridge roofs were duplicated, yet the tin was not. The interior was completely modernized. The building, originally used as a school, became a retirement home for nuns.

The "Croix des Missions" has been at its current site since 1900. The community's records show that the fabrique had maintained an earlier cross before the Sulpicians sold the mill.