Blainville is an off-island suburb of Montreal located in southwestern Quebec, Canada. Blainville forms part of the Thérèse-De Blainville Regional County Municipality within the Laurentides region of Quebec. The town sits at the foot of the Laurentian Mountains and is located 35 kilometres (22 mi) northwest of downtown Montreal.
Louis de Buade de Frontenac granted a vast territory that includes present-day Blainville to elite members of society, lords ("seigneurs") or seigneurs, to promote the development of New France in 1683. The Seigneurie des Mille Îles (Lordship of the Thousand Islands) encompassed over 200 square kilometres (77 sq mi) along the northern shores of the Mille Îles River.
In 1792, a disagreement between Seigneur Hertel and Seigneuresse Lamarque resulted in a division of the seigneurial territory along what was then-called the Great Line (present-day Boulevard du Curé-Labelle or Quebec Route 117).
Blainville is named for the third lord of the seigneurie, Jean-Baptiste Céloron de Blainville (1660-1756).
On 14 June 1968, the parish of Sainte-Thérèse-de-Blainville was divided, and Blainville formed its own town consisting of mostly heretofore undeveloped land. In 2017, the municipality governed 54.62 square kilometres (21.09 sq mi) subdivided into eleven districts, maintained an independent police force with a budget in excess of 14 million CAD and more than 110 staff, a fire department with over 70 firefighters, who since 2016 also serve the neighbouring municipality of Rosemère,, a library with three branches, an arena with two rinks, and an aquatic recreation centre.