Mapocho River

The Mapocho River (Spanish: Río Mapocho) is a river in central Chile. It flows about 110 kilometres (68 mi) from the Andes through the Santiago Metropolitan Region and the capital, Santiago, before joining the Maipo River. Fed by both snowmelt and rain, it runs generally from northeast to southwest through fourteen communes and divides the capital roughly in two.

Santiago was founded on the river's banks in 1541, and the river has shaped the city ever since. Spanish colonial authorities built embankments against its floods, and in the late 1880s engineers confined its central stretch to a concrete channel. For much of the 20th century the Mapocho received most of the city's untreated sewage. A sanitation program completed in 2010 ended the direct discharges, and Santiago's wastewater is now treated. Since then the river has become a focus of urban parks, cultural projects and recreation, and in 2025 Chilean authorities declared its full length an urban wetland. Floods, contamination from mining in the upper basin, and the river's declining water supply remain concerns.