It originates in Ranco Lake and like most of Chile rivers it drains into the Pacific Ocean at the southern boundary of the Valdivian Coastal Reserve.

Traditionally, it marks also the northern boundary of the indigenous Huilliche territory known as Futahuillimapu.

Starting upstream the following settlements lie along the river: Puerto Nuevo at the source, Río Bueno, Trumao, Llancacura, and La Barra at the outflow in the ocean.

[7] This battle ended in clear defeat for the Spanish forces whose pontoon bridge broke apart causing many casualties.

[8] In the years following the battle, the Spanish established a Franciscan mission and a fort next to the river.