Laguna Chasicó is a large endorheic lake located in the partido de Villarino, in the southwest of Buenos Aires province, roughly 80 kilometers from Bahía Blanca and about 700 kilometers from the city of Buenos Aires via Ruta Nacional 3 and Ruta Nacional 22. The lake covers approximately 130 square kilometers with an average depth of around 15 meters, and sits at an elevation of roughly 28 meters below sea level — making the surrounding settlement of Chapalcó the lowest point in Buenos Aires province. Its origin may be tectonic rather than typical lacustrine, the result of an ancient geological fracture, which contributes to its unusual depth and character relative to other pampas lakes.

The water is notably saline, with salinity levels that fluctuate significantly depending on rainfall patterns. During drought years, salinity rises sharply; during wetter periods it moderates. This variability has had a direct impact on the lake's ecology and, by extension, on water-based activities. Paddlers should be aware that the water's high mineral content gives it a distinctive quality different from freshwater lakes in the region.

The lake was declared a provincial nature reserve in 2000 and is managed under provincial law as a Reserva Natural Provincial de Objetivos Definidos Mixtos. The surrounding landscape is ecologically diverse, encompassing sand dunes, grasslands, caldén woodland, salt flats, and freshwater streams within a compact area. The lake has historically supported flamingo colonies attracted by the salinity and the small crustaceans present in the water, and the area supports a range of bird species.

The balneario Chapalcó, located on the lake's shore, has historically served as the main access point for visitors and offers camping facilities, accommodation options, and beach areas. Aquatic sports are available at the site. The settlement developed as a resort destination beginning in the 1930s, partly on account of the water's reputed therapeutic properties.

Paddlers planning a visit should note that the lake's ecological and tourism situation has been under stress in recent years due to prolonged drought and elevated salinity, which affected fish populations and led to reduced visitor activity. Conditions are expected to gradually improve, but the overall state of the lake's ecosystem remains in recovery.