Located on the southeastern coast of India, Chennai sits on the Coromandel Coast off the Bay of Bengal. The city is built on a relatively flat coastal plain known as the Eastern Coastal Plains. Its physical geography is heavily defined by its proximity to the ocean and its network of urban waterways.
Three major rivers flow through Chennai: the Kosasthalaiyar to the north, the Cooum in the central region, and the Adyar in the south. A significant artificial canal, the Buckingham Canal, runs parallel to the coast, linking these rivers. The city's western and southern fringes are dotted with several large lakes and reservoirs, such as Red Hills, Sholavaram, Chembarambakkam, and Porur, which serve as crucial freshwater sources.
Chennai's coastline features several prominent beaches, most notably Marina Beach and Elliot's Beach (Besant Nagar). The southern part of the city is also home to the Pallikaranai wetland, a vital freshwater marsh that supports a diverse range of flora and migratory birds, though urbanization has heavily impacted it in recent decades.