The Bolaños River is a river in Mexico flowing through the Sierra Madre Occidental, and a tributary of Río Grande de Santiago.

The river's origin is in the state of Zacatecas, about 60 km (37 mi) west of the city of Fresnillo, about 40 km (25 mi) south of Tropic of Cancer.

It enters the state of Jalisco some 85 km (53 mi) later, eventually draining into the Lerma Santiago River, approximately 40 km (25 mi) northwest of the city of Tequila.

The last 32 km (20 mi) of the river form the boundary between the states of Jalisco and Nayarit.

The principal municipalities transversed by the Bolaños River include: