Mille-Isles is located in the South-East of the Laurentides Region, in the Argenteuil Regional County Municipality, west of Saint-Jérôme and near urban centres such as Montreal and the Gatineau-Ottawa Region. It has a population of 1500.
The topography of this municipality of modest size is very irregular, and its territory is doted with well-stocked lakes, interspersed with hills and criss-crossed by rivers.
Mille-Isles was named after the seigniory of Milles-Isles, as per the original written form. This entity was first created in 1683 and ceded to Michel-Sidrac Dugué de Boisbriand. In 1714, it was further ceded to Charles-Gaspard Piot de Langloiserie and Jean Petit, respective spouses of Marie-Thérèse Dugué and Charlotte Dugué, daughters of the first lord.
Finally, in 1752, the territory was augmented and the new part was granted to Eustache Lambert Dumont. It is on this territory that the municipality would be established.
The presence of many water bodies and islands justifies, firstly, the name of the river (Mille-Ilesin French is Thousand Islands).
The first settlers came from Ireland around 1850, and the municipality was officially erected in 1855 following its separation from the Parish of Saint-Jérôme. This explains why the only name of inhabitants used for Mille-Isles citizen is the English form, Mille-Isler. Today however, only about 30% of the inhabitants speak English as their first language and about 70% speak French.