Puelo Lake, Glacial lake in Chubut Province, Argentina.

Puelo Lake is a narrow, L-shaped lake of fluvial-glacial origin in northern Chubut Province, Argentina. It reaches a maximum depth of 180 metres and is fed by the Azul and Quemquemtreu rivers. The lake lies within Lago Puelo National Park and is surrounded by Valdivian temperate rainforest, vegetation more typical of Chile than of the eastern Andes.

The lake lies in a fluvial-glacial basin in northern Chubut, within Lago Puelo National Park and Reserve. Its name derives from the Mapuche puel-có, "water of the east", because its sources lie east of the Andes high summits even though its outflow reaches the Pacific. The town of Lago Puelo, 5 km north in the Azul River valley, grew around tourism.

The name derives from Mapudungun puel-có: puel, "east", and co, "water", so "water of the east". The lake and its sources lie east of the high Andes, yet its outflow, the Puelo River, drains west through Chile to the Pacific. The town of Lago Puelo, 5 km north in the Azul valley, shares the name.

Two camping areas near the lake offer different accommodation options for overnight stays. One site provides organized facilities while the other allows free camping without structured infrastructure.

Water from the lake flows through the Puelo River, crossing into Chile and reaching the Pacific Ocean via a narrow, turbulent channel. This cross-border waterway creates a direct hydrological link between Argentina and Chile's coastline.