The Iroquois River is a tributary of the Saint John River (Bay of Fundy) emptying in New Brunswick, in Canada. This river flows into the Notre Dame Mountains, in the municipality of Dégelis, Quebec, in Temiscouata Regional County Municipality (RCM), in administrative region of Bas-Saint-Laurent, in Quebec; and in the Madawaska County, in New Brunswick, in Canada.
The Iroquois River flows south especially in forest areas, more or less in parallel, between the Little Iroquois River (East side) and the Madawaska River (Saint John River).
The Iroquois River flows on the north shore of Saint John River (Bay of Fundy). The latter flows southeast through all the New Brunswick province and pours on the north bank of the Bay of Fundy which is opened to the southwest on the Atlantic Ocean.
The Iroquois River originates at the mouth of Lake Iroquois (length: ; altitude: ), located in the municipality of Dégelis, Quebec, in MRC Témiscouata Regional County Municipality (RCM). This lake is located in a small valley facing southeast, which counts ten lake. This valley extends to the northwest on the other river side, part of the Owen River.
The mouth of Lake Iroquois is located at:
The Iroquois River, which flows on , according to the following segments:
Lower course of the river (segment of )
From the mouth of Lake Iroquois, the Iroquois River flows over:
Lower course of the river (segment of )
From the confluence of the Little Iroquois River, the Iroquois River flows over:
The Iroquois River flows on the north shore of Saint John River (Bay of Fundy) on the west side of the area designated "Platin of St. Basil", facing the border of Maine. This confluence is located at:
The toponym "Iroquois River" was made official on August 17, 1978 at the Commission de toponymie du Québec (Quebec Geographical Names Board).