The Río Ameca is a river

River

A river is a natural watercourse, usually freshwater, flowing towards an ocean, a lake, a sea, or another river. In a few cases, a river simply flows into the ground or dries up completely before reaching another body of water. Small rivers may also be called by several other names, including...

 of some 230 km in length in western Mexico

Mexico

The United Mexican States , commonly known as Mexico , is a federal constitutional republic in North America. It is bordered on the north by the United States; on the south and west by the Pacific Ocean; on the southeast by Guatemala, Belize, and the Caribbean Sea; and on the east by the Gulf of...

.
It rises in the Bosque de la Primavera in Jalisco

Jalisco

Jalisco officially Estado Libre y Soberano de Jalisco is one of the 31 states which, with the Federal District, comprise the 32 Federal Entities of Mexico. It is located in Western Mexico and divided in 125 municipalities and its capital city is Guadalajara.It is one of the more important states...

, 23 km to the west of state capital Guadalajara; flows through the city of Ameca

Ameca, Jalisco

Ameca is a city and municipality, in Jalisco in central-western Mexico. The municipality covers an area of 685.73 km². The city is bisected by the Ameca River which drains to the Pacific Ocean near Puerto Vallarta....

; and then forms the boundary between Jalisco

Jalisco

Jalisco officially Estado Libre y Soberano de Jalisco is one of the 31 states which, with the Federal District, comprise the 32 Federal Entities of Mexico. It is located in Western Mexico and divided in 125 municipalities and its capital city is Guadalajara.It is one of the more important states...

 and Nayarit

Nayarit

Nayarit officially Estado Libre y Soberano de Nayarit is one of the 31 states which, with the Federal District, comprise the 32 Federal Entities of Mexico. It is divided in 20 municipalities and its capital city is Tepic.It is located in Western Mexico...

 on its way to the Pacific Ocean

Pacific Ocean

The Pacific Ocean is the largest of the Earth's oceanic divisions. It extends from the Arctic in the north to the Southern Ocean in the south, bounded by Asia and Australia in the west, and the Americas in the east.At 165.2 million square kilometres in area, this largest division of the World...

, where it drains into the Bahía de Banderas

Bahía de Banderas

Bahía de Banderas is both a bay and a municipality in the Mexican state of Nayarit.The bay, site of the tourist destination Puerto Vallarta, is bounded on the north by Punta Mita and on the south by Cape Corrientes...

 near Puerto Vallarta, Jalisco. Its main tributaries are the Ahuacatlán and Amatlán de Cañas.