In the end, this river crosses the Saguenay Fjord National Park.

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

The main hydrographic slopes near the Saint-Étienne River are: The Saint-Étienne River rises at the mouth of Lac des Côtes (length: 0.6 km (0.37 mi); altitude: 132 m (433 ft)).

From its source (Lac des Côtes), the course of the Saint-Étienne River descends on 4.8 km (3.0 mi) according to the following segments: 2.9 km (1.8 mi) northerly in a confined valley to the outlet (from the southeast) of an unidentified lake; 1.5 km (0.93 mi) northerly in a concealed valley to the outlet (coming from the west) of Lac Fidelin; 0.4 km (0.25 mi) blaster in a valley through Saguenay Fjord National Park to its mouth.

The toponym "Saint-Étienne River" was formalized on December 5, 1968, at the Bank of Place Names of the Commission de toponymie du Québec.