Río Cerrillos has its origin in barrio Anón and runs south until it feeds into Bucaná River.The river continues its southern course parallel to PR-139 for 5 kilometers until it reaches PR-5139.[8][9] The following table summarizes the course of Río Cerrillos in terms of roads crossed.Roads are listed as the river flows from its origin in the mountains of Barrio Anón, north of the city of Ponce, to its merging with Río Bayagán in Barrio Machuelo Arriba to form Río Bucaná (N/A = Data not available): Cerrillos is the feeder river for Lake Cerrillos Dam in Barrio Maragüez, in the municipality of Ponce.The lake is surrounded by the Cerrillos State Forest north of the dam.