The latter being the southernmost receives water from the Patapédia East River which defines a segment of boundary between the Quebec and New Brunswick.

The Mitis dam is built at the mouth of "lac inférieur" (Lower Lake), located at the west end, near the hamlet of Lac-Mitis.

Dams of "Mitis-One" and "Mitis-Deux", located on the border of the municipalities of Sainte-Flavie and Grand-Métis near Mont-Joli harness the river near its mouth.

After a descent of 74 kilometres (46 mi), the river flows into the Gulf of St. Lawrence in the Mitis Bay, protected by a headland, named the "Pointe aux Cennelles" in Sainte-Flavie .

[3] Since July 23, 2014 data, the law requires fishermen to apply the thought to water all large salmon caught.