The Río Tapenagá is a 300-kilometer waterway located primarily in the province of Chaco, Argentina, with its lower course passing through the province of Santa Fe before emptying into the Río Paraná Miní at approximately 28°04′45″S, 59°09′22″W. The name derives from the indigenous words "tape" (road) and "naga" (souls).

The river flows through lush, humid woodland interspersed with water hyacinths and irupés (giant water lilies). The surrounding terrain features clay soils and an irregular forest canopy. The water is clear and notably fresh, fed by rainfall from the Bajos Submeridionales and the region's high ambient humidity. The river transports between 3 and 8 percent of the total water accumulated within its catchment basin.

The clay soils and irregular vegetation cover contribute to an uneven flow regime throughout the year compared to other rivers in the region, which is a relevant consideration for trip planning. Paddlers should be aware that water levels and current conditions can vary considerably depending on seasonal rainfall patterns.

The corridor along the river, known locally as the "línea Tapenagá," has some ecotourism infrastructure in the form of cabins. The river is also crossed by bridges constructed from algarrobo and quebracho timber, some of which are over 100 years old, providing points of historical and cultural interest along the route. The lower section of the river, near Florencia in the province of Santa Fe, is accessible from the Ruta Nacional N°11 bridge, which represents one documented crossing point.

The overall character of the paddling environment is defined by dense riparian woodland, aquatic vegetation, and relatively clear water in a flat, low-lying landscape typical of the Chaco region.