It then flows southwest and west, and eventually northwest into the city of Concepción, Chile. After the city of Concepción, it flows north through the former villages (now neighbourhoods) of Andalién and El Rosal, and then the communes of Talcahuano, and Penco. There, on its alluvial plain northeast of Concepción, it forms distributaries, and small lakes, such as the Laguna Negra, before entering the Bay of Concepción.