The 62,300-hectare Angat Watershed Reservation lies at the Southernmost tip of the Sierra Madre mountain range and straddles the towns of Dona Remedios Trinidad, Norzagaray, and San Jose Del Monte in Bulacan

Its principal river, Angat River, supplies water to both the Angat Dam and the La Mesa Dam. Angat Dam irrigates more than 30,000 hectares of prime agricultural lands in Bulacan and feeds some 200 Megawatt of hydroelectric power to the Luzon grid.

La Mesa Dam, on the other hand, brings domestic water to some 12 million people of Metro Manila. Some portions of Cavite also depend on La Mesa Dam for their water requirements.

The Angat Watershed Reservation is home to some 500 indigenous Dumagat families, and is the focus of major forest protection and conservation efforts of DENR Region III.