The Río Conlara is the principal river of the Valle de Conlara in the northeastern part of San Luis province, Argentina. It originates in the Sierras de San Luis and flows roughly 180 kilometers in a south-to-north direction — an orientation notable in the Southern Hemisphere — before terminating in the Bañados de Las Cañadas, an endorheic wetland system where the water becomes subsurface. The river runs through the valley between the Sierra de Comechingones to the east and the Sierras de San Luis to the west, passing through the towns of Renca, Tilisarao, San Pablo, Concarán, and Santa Rosa del Conlara along its course.

The river's flow is seasonal, with water levels varying considerably depending on rainfall. During drier periods, flow can be reduced significantly, which is a practical consideration for anyone planning a paddling trip. The river can be visited year-round, though conditions differ substantially between seasons.

The town of Santa Rosa del Conlara hosts the Complejo Municipal Río Conlara, the largest balneario in the province, with beach areas, picnic zones, and camping facilities. This area is accessible from Merlo and is situated near the Route 2 bridge. Access to natural river areas is generally free, though specific balneario complexes may charge an entrance fee. Parking at popular spots can be limited during peak summer periods.

The overall character of the river in its accessible stretches is calm and family-oriented, with the balneario areas featuring designated swimming pools suitable for different age groups. Whitewater sections, paddling-specific hazards, and formal put-in and take-out points for canoes or kayaks have not been documented.