Arroyo Pindapoy Grande is a freshwater stream flowing through the province of Misiones, Argentina, within the greater Plata river basin. Its name derives from the Guaraní phrase pinda po'i, meaning "fine fishhook" — a fitting name for a waterway that has long drawn the attention of local anglers. The stream originates in the Sierras de San José and flows until it joins the Arroyo Garupá to the east of the town of the same name. Along its course, it receives several tributaries, including the Arroyo Tororó and Arroyo Pindapoy Chico from the left bank, and the Arroyo Guasupí from the right. Of particular geological interest, part of the Pindapoy Grande follows an ancient channel — a paleocauce — of the Río Paraná, from a time when that great river drained eastward through the Garupá, Pindapoy, and Río Aguapey systems toward the Río Uruguay. This ancient heritage gives the stream a distinctive character, with a meandering lower course that transitions into a sub-reservoir environment near its confluence with the Garupá.