Pasig River

The Pasig River (Filipino: Ilog Pasig; Spanish: Río Pásig) is a water body in the Philippines that connects Laguna de Bay to Manila Bay. Stretching for 25.2 kilometers (15.7 mi), it bisects the Philippine capital of Manila and its surrounding urban area into northern and southern halves. Its major tributaries are the Marikina River and San Juan River. The total drainage basin of the Pasig River, including the basin of Laguna de Bay, covers 4,678 square kilometers (1,806 sq mi).

The Pasig River is technically a tidal estuary, as the flow direction depends upon the water level difference between Manila Bay and Laguna de Bay. During the dry season, the water level in Laguna de Bay is low with the river's flow direction dependent on the tides. During the wet season, when the water level of Laguna de Bay is high, the flow is reversed towards Manila Bay.

The Pasig River used to be an important transport route and source of water for Spanish Manila. Due to negligence and industrial development, the river suffered a rapid decline in the second half of the 20th century and was declared biologically dead in 1990. Two decades later after that declaration, however, a renaturation program designed to revive the river has seen the return of life to the river, including eight fish species, 39 species of birds, and 118 species of trees and other vegetation. As a result, the Pasig River received the Asian River Prize by the International River Foundation (IRF) in 2019.

The Pasig River Rehabilitation Commission (PRRC) was a Philippine government agency established to oversee rehabilitation efforts for the river from 1999 until it was abolished in November 2019. Rehabilitation efforts are also aided by private sector organizations, such as the Clean and Green Foundation, Inc., which ran the Piso para sa Pasig (Filipino: "A peso for the Pasig") campaign in the 1990s.