The rivière des Aulnaies is a tributary of the Saguenay River, flowing on the northwest shore of the Saint Lawrence River, successively in the municipalities of Bégin and Saint-Ambroise, in the Le Fjord-du-Saguenay Regional County Municipality, in the administrative region of Saguenay–Lac-Saint-Jean, in the Province of Quebec, in Canada.

This mouth is located at: The 1852 map designed by provincial surveyor Frederic William Blaiklock refers to the toponym "R. Des Aunes".

The land surveyor Jean Maltais, in his report on the township of Bégin, in 1895, mentions “the river of Aulnaies”.

Appeared in Regions of Quebec, Lac-Saint-Jean, Chicoutimi and the north coast of the St. Lawrence, Description of surveyed cantons, explorations of territories and surveys of rivers and lakes, from 1889 to 1908, published by the Department des Terres et Forêts, Québec, 1908, page 6.

[4] The toponym of "Rivière des Aulnaies" was formalized on December 5, 1968, at the Place Names Bank of the Commission de toponymie du Québec.