Lac Waposite is a freshwater lake covering 24.5 km² in the Nord-du-Québec region of Quebec, Canada, situated at approximately 50°15′N, 75°19′W within the Eeyou Istchee James Bay Regional Government area. Its name derives from the Cree language, meaning "barren landscape with many rocks," which reflects the character of the surrounding terrain. The lake features an irregular shape with alternating widenings and narrows, a form attributed to glacial processes, making for a varied paddling environment across its considerable surface area.

The lake lies within the proposed Parc national Assinica and the Assinica Wildlife Sanctuary, situated in the Rupert Plateau natural region. The surrounding landscape is dominated by boreal forest of black spruce and jack pine, interspersed with peatlands and rocky knolls rising 50–100 m above the surrounding terrain. The area is noted as fire-prone. Lac Waposite drains northward into the Broadback River watershed through connections to lakes including Comencho and Assinica.

Access to Lac Waposite is significantly limited by its remote location. There is no direct road connection to the lake; the nearest forest road is approximately 35.6 km to the southeast, skirting Mount Opémisca and connecting to Quebec Route 113 and the Canadian National Railway line near Chapais. The lake lies roughly 66.6 km northwest of Chibougamau and 58.5 km northwest of Chapais. This degree of remoteness means that any paddling trip to Lac Waposite requires serious logistical planning, likely involving fly-in access or an extended overland approach. Paddlers should be prepared for full self-sufficiency given the absence of nearby infrastructure or amenities.

The toponym Lac Waposite was officially recognized by the Commission de toponymie du Québec on December 5, 1968. The lake sits north of the 50th parallel in a region with a subarctic climate, which has direct implications for trip timing; the paddling season is relatively short, constrained by ice cover during the long winter months. Paddlers considering a trip here should account for the wilderness character of the Assinica Wildlife Sanctuary context and any regulations that may apply within that protected area designation.