The surface of the Cascouia River is usually frozen from the beginning of December to the end of March, however the safe circulation on the ice is generally made from mid-December to mid-March.

One of the first known mentions of the Innu word "Cascaouia" is attributed to the surveyor Joseph-Laurent Normandin, in 1732, who wrote in his Journal: "...

There is a large bay, which is bordered by jongs and grasses, that the Indians call Les Gachek8illaces de Quinongamingue ”.

By modifying its primitive form in order to facilitate its use, the first explorers perpetuated this Amerindian term meaning "grasslands" or "rushes".

[4] The toponym “rivière Cascouia” was formalized on December 5, 1968, at the Place Names Bank of the Commission de toponymie du Québec.