Embalse Cruz de Piedra is a reservoir located in the town of Juana Koslay, in the Departamento Juan Martín de Pueyrredón, approximately 14 km east of the city of San Luis. Completed in 1941, it is one of the oldest hydraulic works in the province. The dam wall stands roughly 25–29 meters high and impounds a water surface of 154 hectares with a storage capacity of 12.5 cubic hectometers. The reservoir is fed by the Río Volcán, the Cuchi Corral, and the arroyo Los Puquios, draining a catchment of approximately 150 km². A hydroelectric plant is located at the base of the dam and supplies power to the provincial capital and the community of Las Chacras.

The reservoir supports kayaking, rowing, sailing, and motorized watercraft in designated zones. Fishing is also practiced here, with pejerrey (Argentinian silverside) and common carp present; regulations include a minimum size of 25 cm and a daily limit of 35 pejerrey, and nighttime fishing from a vessel is prohibited. Equipment rental is available through Náutica Fabre, located at Buenos Aires 884 in San Luis Capital.

Access is straightforward via paved roads that circle the reservoir. A dirt track branches off to reach the shoreline, where there is a beach area, though no lifeguard service is provided. Viewpoints with seating and shade structures are positioned along the surrounding roads. The reservoir is most heavily visited on weekends, particularly Sunday afternoons, when it draws families and recreational users from the capital. Weekday mornings offer considerably quieter conditions.

The water surface is surrounded by green vegetation and framed by the surrounding hills, giving the reservoir a visually open character. The proximity to San Luis city — roughly a 15-minute drive — means the site can be busy during summer and on weekends. Paddlers looking for a straightforward, accessible flatwater outing close to urban infrastructure will find the reservoir well-suited to that purpose, while those seeking solitude may prefer early weekday visits.