The Lake General Carrera (Chilean side) or Lake Buenos Aires (Argentine side) is a lake located in Patagonia and shared by Argentina and Chile. Both names are internationally accepted.

The lake has a surface of 1,850 km² of which 970 km² are in the Chilean Aisén Region, and 880 km² in the Argentine Santa Cruz Province, making it the biggest lake in Chile, and the fourth largest in Argentina. In its western basin, Lake Gen. Carrera has 586 m maximum depth.

The lake is of glacial origin and is surrounded by the Andes mountain range. lake drains to the Pacific Ocean on the west through the Baker River.

The weather in this area of Chile and Argentina is generally cold and humid. But the lake itself has a sunny microclimate, a weather pattern enjoyed by the few settlements along the lake, such as Puerto Guadal, Puerto Ingeniero Ibáñez and Chile Chico in Chile, and Los Antiguos and Perito Moreno in Argentina.

The area near the coast of the lake was first inhabited by criollos and European immigrants between 1900 and 1925. In 1971 and 1991, eruptions of the Hudson Volcano severely affected the local economy, especially that of sheep farming.