The Rivière Ouiatchouaniche is a 65.7-kilometre river located in the Le Domaine-du-Roy Regional County Municipality within the Saguenay–Lac-Saint-Jean administrative region of Quebec. It originates at Quentin Lake in the unorganized territory of Lac-Ashuapmushuan at an elevation of 301 metres and flows northward through the municipality of Sainte-Hedwidge before reaching the city of Roberval, where it empties into Lac Saint-Jean at an elevation of 101 metres. From Lac Saint-Jean, water continues into the Saguenay River system.

The river passes through terrain that transitions from forested upper and intermediate sections, where forestry is the primary land use, to agricultural land in the lower reaches near the mouth. The upper portion of the valley is accessed via forest roads. The river also falls within the Zec de la Lièvre territory, which may carry specific access or activity regulations that paddlers should verify before planning a trip.

Canot Kayak Québec has produced a dedicated digital map for the river, available free through the Avenza Maps app (iOS and Android), published in April 2023. This map covers the full paddling route and marks put-in and take-out points, rapids, portages, camping sites, and other points of interest along the corridor. The presence of marked rapids and portages indicates the river includes whitewater sections requiring portaging in places.

The river also supports fishing, with northern pike, walleye, and brook trout among the species reported by anglers. The Ouiatchouaniche is listed as a recognized canoe route in Quebec paddling resources, confirming its use as a multi-day paddling destination. The river's name derives from an Indigenous term translating roughly to "the little river where the current is," reflecting its character as a moving-water route rather than a flatwater paddle.

Paddlers planning a trip should consult the Canot Kayak Québec map for detailed route information and should investigate any regulations associated with the Zec de la Lièvre, as controlled zones in Quebec typically require permits for access and overnight use.