The Río Ameca is a river of some 230 km in length in western Mexico. It rises in the Bosque de la Primavera in Jalisco, 23 km to the west of state capital Guadalajara; flows through the city of  Ameca; and then forms the boundary between Jalisco and Nayarit on its way to the Pacific Ocean, where it drains into the Bahía de Banderas at Puerto Vallarta, Jalisco. Its main tributaries are the Ahuacatlán and Amatlán de Cañas.