Prieto River is a river in the municipality of Ponce, Puerto Rico. It is located in the northeastern area of the municipality. Forming at an altitude of , RÃÂo Prieto originates at the second highest point of any river in the municipality after RÃÂo Inabon. It empties into RÃÂo Cerrillos. Together with RÃÂo Blanco, RÃÂo Prieto is one of the two rivers in Ponce with mouths at the highest elevation (both at ). This river is one of the 14 rivers in the municipality.
RÃÂo Prieto has its origin in barrio Anón in Ponce, in the area of Toro Negro State Forest, half a kilometer southwest of Cerro Jayuya and about 0.75 kilometer southeast of Cerro de Punta. It is a tributary of RÃÂo Cerrillos and part of the RÃÂo Bucana watershed.
Running south from its origin, RÃÂo Prieto runs for about 3 kilometers before it is fed by Rio Blanco. RÃÂo Prieto winds its way through the mountains paralleling PR-139 for about 1 kilometer before it feeds into RÃÂo Cerrillos approximately 800 feet west of the intersection of PR-139 and Camino Cerrillo in Barrio Anón.