Lago Marí Menuco is a large artificial reservoir nestled in the Confluencia Department of Neuquén Province, in Argentine Patagonia. Formed as part of the Cerros Colorados hydroelectric complex alongside the neighboring Lago Los Barreales, the lake sits at an elevation of 414 meters above sea level and covers a surface area of approximately 173.9 square kilometers, with a shoreline stretching roughly 77.5 kilometers. The reservoir was created by a diversion dam on the Río Neuquén, and its waters feed the Planicie Banderita Hydroelectric Plant, which generates approximately 1,500 million kWh per year. The lake receives inflow from Lago Los Barreales to the north, and its effluent drains back into the Río Neuquén. The surrounding landscape is characteristic of Patagonian steppe — open terrain with abundant vegetation along the shoreline, set against a backdrop typical of the region's cold, dry climate.