Chennai Port, formerly known as Madras Port, is the second largest container port of India, behind Mumbai's Jawaharlal Nehru Port also known as Nhava Sheva. The port is the largest one in the Bay of Bengal. It is the third-oldest port among the 13 major ports of India with official port operations beginning in 1881, although maritime trade started much earlier in 1639 on the undeveloped shore. It is an artificial and all-weather port with wet docks. Once a major travel port, it became a major container port in the post-Independence era. An established port of trade of British India since the 1600s, the port remains a primary reason for the economic growth of Tamil Nadu, especially for the manufacturing boom in South India, and has contributed greatly to the development of the city of Chennai. It is due to the existence of the port that the city of Chennai eventually became known as the Gateway of South India.

The Bay of Bengal is the northeastern part of the Indian Ocean. The world's largest bay, geographically it is positioned between the Indian subcontinent and the Indochinese peninsula, located below the Bengal region.