Lago Bertrand is a glacially fed lake in the Aysén del General Carlos Ibáñez del Campo Region of Chilean Patagonia, covering a surface area of 67.5 square kilometers (26.1 square miles). It sits at coordinates 46°55′S 72°50′W, surrounded by mountains and dense native forest. The lake receives its primary inflow from Lago General Carrera to the north and is separated from Lago Plomo by a terminal moraine. At its southern tip, the village of Puerto Bertrand marks the origin of the Río Baker, Chile's largest river by water volume, which flows westward toward the Pacific Ocean.

The water has a notably turquoise color, a characteristic of glacial runoff from the surrounding mountain ranges. The lake's remote setting within the broader Patagonian wilderness means the surrounding landscape is largely undeveloped, with native forest reaching down toward the shoreline. Lago Plomo, which lies adjacent and is separated by the terminal moraine, carries grey-colored water, creating a visible contrast between the two lakes.

Kayaking is a recognized activity on the lake, and the area around Puerto Bertrand serves as the primary access point at the southern end. The lodge known as The Meeting Waters, accessible only by boat, sits on the lake's shores and offers paddling as one of its featured activities, suggesting that the lake's conditions are suitable for recreational paddling. The Cordón Contreras summits flank the lake to the west.

Patagonia's weather patterns are a primary consideration for any paddling trip in this region. The area is known for strong and unpredictable winds, which are a standard hazard throughout the Aysén Region. The lake's glacial origins mean water temperatures are cold year-round. The Carretera Austral passes through the broader area, making vehicle access to Puerto Bertrand feasible from Balmaceda Airport (near Coyhaique), approximately four hours by road.