The Río Reñileuvú is a river in northern Neuquén province, Argentina, originating in the Andes mountains. It flows for 78 kilometers before joining the larger Río Neuquén. The river's source is at an elevation of 1,240 meters, and its mouth is at 860 meters above sea level. Its course begins from the waters of the arroyo Piuquenes. The river is part of the Río Neuquén system. The river's character, based on its geographical setting, suggests a mountain and foothill environment.