Bengal, Bay of, arm of the Indian Ocean, between India on the west and Myanmar (formerly known as Burma) and the Malay Peninsula on the east. In the southeast, the Andaman and Nicobar islands, formed by the peaks of a submerged mountain range, separate the Bay of Bengal from the Andaman Sea. The area experiences monsoons in both winter and summer, followed by cyclones in spring and fall. Many large rivers flow into the bay, including the Ganges and the Brahmaputra on the north. The two rivers have deposited a huge layer of sediments, called the Ganges Fan, about 2,000 km (about 1,000 mi) into the bay. The Mahanadī, the Godavari, the Krishna, and the Kaveri (Cauvery) rivers flow in on the west.


The western coast of the bay has few natural harbors. The city of Chennai (Madras) built an artificial harbor on the sandy Coromandel Coast, and it is now one of India’s most important ports. The east coast has many natural harbors, including Sittwe in Myanmar. The bay is 2,100 km (1,300 mi) long and 1,600 km (1,000 mi) wide.