The village of Coteau Saint-Louis sprang up in 1846 around the Dubuc and Limoges quarries, today buried beneath Laurier Park. Gilford Street (see attractions) follows the route of the old quarry road. The limestone from the quarries, for which Montreal was famous, was used in many local buildings and monuments, including Notre-Dame Church and Bonsecours Market.

The busy quarries and the establishment of the Plessis-Bélair tannery, at the intersection of what are today Mont-Royal Avenue and Henri-Julien Street, led to the founding of the village of Saint-Jean-Baptiste in 1860.

Many stories are told about the quarry workers and tanners. For instance, it is said that the quarry workers loved walking about barefoot once their day’s work was done, leading passers-by to dub them "pied-noirs," meaning "black-feet." Another story is that a rivalry sprang up between quarry workers and tanners, leading to legendary battles at regular intervals between the "black-feet" and the "yellow-nostrils" from the tanneries.

In 1860, horse-drawn tramways climbing up the hill from Sherbrooke also made their first appearance. The Plateau’s first public-transit system transformed it from a rural area into a suburb of Montreal. At the same time, farmland was sold off and many streets were laid out. For example, landowner Cadieux de Courville had houses built on his property extending from Sherbrooke Street to Mont-Royal Avenue and from Coloniale Avenue to Hôtel-de-Ville Street. He played a leading role in determining the layout of the neighbourhood. Other landowners – Guy, Cherrier, Viger and Papineau – followed suit, dividing their farmland into lots as far as Papineau Street.