Chennai features remarkably flat topography, typical of coastal plains, with an average elevation of just 6.7 meters (22 feet) above sea level.
* **Highest Point:** St. Thomas Mount, a small hillock rising to about 91 meters (300 feet), and the Pallavaram hills in the southwest. * **Lowest Point:** Sea level along the Bay of Bengal coastline. * **Coastal Areas:** Characterized by expansive, flat sandy beaches, most notably Marina Beach and Elliot's Beach. * **Flood Plains:** Much of the city is built on the historical flood plains of the Adyar and Cooum rivers, rendering certain low-lying areas highly susceptible to inundation during heavy monsoons.