Manila Bay is one of the finest natural harbors in the world which serves the port of Manila (on Luzon), in the Philippines. The entrance is 19 km wide and expands to a width of 48 km. Mariveles, in the province of Bataan, is an anchorage just inside the northern entrance and Sangley Point is the former location of Cavite Naval Base.
On either side of the bay are volcanic peaks topped with tropical foliage: 40 km to the north is the Bataan Peninsula and to the south is the province of Cavite.
Across the entrance to Manila Bay are several islands. The largest is Corregidor, which is 3 kilometers from Bataan and, along with the island of Caballo, separates the mouth of the bay into the North and South Channels. In the south channel is El Fraile Island and outside the entrance, and to the south, is Carabao Island. El Fraile, a rocky island some 4 acres (16,000 m²) in area, supports the massive concrete and steel ruins of Fort Drum, an island fortress constructed by the United States Army to defend the southern entrance of the bay. To the immediate north and south are additional harbors.
The bay was the setting for the Battle of Manila Bay in 1898 and the siege of Corregidor Island by invading Japanese forces in 1942.