Rohault Lake is a freshwater body of the unorganized territory of Lac-Ashuapmushuan, Quebec, in the western part of Le Domaine-du-Roy, in the administrative region of Saguenay-Lac-Saint-Jean, in province of Quebec, in Canada.

The western part of the Lake Rohault hydrographic slope is accessible via the R1032 forest road (North-South direction).

The forest road route 167 passes north-east of Nicabau Lake, connecting Chibougamau to Saint-Félicien, Québec.

The surface of lake Rohault is usually frozen from early November to mid-May, however, safe ice circulation is generally from mid-November to mid-April.

On the east side, Gaudreau Bay extends northward for 11.6 kilometres (7.2 mi).