The Río Caleufú is a roughly 50-kilometer river in the southern part of Neuquén Province, Argentina, formed by the confluence of the Río Filo Hua Hum and the Río Meliquina within the Departamento Lácar. It flows eastward, dropping from approximately 730 meters at its source to around 550 meters at its mouth, where it joins the Río Collón Curá as a tributary of the Río Negro basin.

The river's character changes noticeably along its length. The upper section is steeper, with a higher gradient, abundant rapids, a rocky riverbed, and dense riparian vegetation. This stretch offers more dynamic water for paddlers. The lower section flattens out considerably, with the river tending to form meanders and braided channels. Riparian vegetation largely disappears in the lower reaches, giving way to steppe landscape. The riverbed substrate shifts from larger cobbles and boulders upstream to finer sediments and sand downstream. Water clarity also changes: the upper river runs cleaner and clearer, while the lower section carries more turbidity and takes on a brownish tone associated with higher biological productivity and a denser fish population.

One notable feature along the river is the Pozones del Caleufú, a section where the channel narrows and the water has carved deeply into the rock over time, creating tunnels and large, deep pools with a striking turquoise color. The water in this zone is calm and clear enough to observe trout moving below the surface. The surrounding landscape includes mountains, pine forests, and native vegetation.

Both whitewater descent and sport fishing are practiced on the river. Summer is the most favorable season for visiting and paddling the river. To reach the Pozones area, one route involves traveling approximately 27 km from San Martín de los Andes along Ruta 40, then taking RP 63 for roughly 15 km to Villa Meliquina; the final approach involves a gravel road. The Pozones are located approximately 20 km from Villa Meliquina.