Between 1640 and 1700, a settlement formed inside a large horseshoe-shaped meander of the L'Assomption River.

They would drag their canoes across the peninsula as a short-cut for the meander, and therefore the settlement was first called Le Portage.

Between 1774 and 1888, L'Assomption was the most prosperous and important town between Montreal and Trois-Rivieres.

[2] In December 2010, the 1,300-worker Electrolux factory announced that it would close, relocating to Memphis, Tennessee.

It operates many francophone public schools, both at the elementary and high school levels, including: The city is also home to the Collège de L'Assomption, a private High School of historical renown,[13] as well as the Cégep Régional de Lanaudière in l'Assomption.