The topography of Pondicherry is strikingly flat and low-lying, with an average elevation of just 3 meters (10 feet) above sea level.
* **Coastal Areas**: The eastern boundary is defined by the Bay of Bengal. To combat severe coastal erosion, a prominent sea wall made of granite boulders was constructed along the city's famous Promenade Beach. * **Rivers and Estuaries**: The Ariyankuppam, Sankaraparani (Gingee), and Pennaiyar rivers flow through the surrounding district, creating minor estuaries and backwaters before emptying into the sea. * **Highest and Lowest Points**: The elevation varies minimally; the lowest point is at sea level along the coast, and the highest point within the immediate urban area does not exceed 10-15 meters.