Its source is in the Cordillera Central mountain range west of Adjuntas, and it flows about  westward to its mouth on the Mona Passage  north of Mayagüez.
The river's source is found in the Cordillera Central mountain range to the west of Adjuntas, and from there it flows roughly westward until it discharges into the Mona Passage, located north of Mayagüez.