Manila Bay is a natural harbour that serves the Port of Manila, in the Philippines. It is located around the capital city of the Philippines. Manila Bay facilitated trade between the Philippines and its neighbouring countries. With an area of 1,994 km² (769.9 sq mi), and a coastline of 190 km (118.1 mi), Manila Bay is positioned in the western part of Luzon and is bounded by Cavite and Metro Manila on the east, Bulacan and Pampanga on the north, and Bataan on the west and northwest. Manila Bay drains approximately 17,000 km² (6,563.7 sq mi) of watershed area, with the Pampanga River contributing about 49% of the freshwater. With an average depth of 17 m (55.8 ft), it is estimated to have a total volume of 28.9 billion cubic metres (28.9 cubic km). Entrance to the bay is 19 km (11.8 mi) wide and expands to a width of 48 km (29.8 mi). However, width of the bay varies from 22 km (13.7 mi) at its mouth and expanding to 60 km (37.3 mi) at its widest point.