The topography of Campbell Bay and the surrounding Great Nicobar Island is rugged and varied. The coastal areas, where the town is situated, consist of narrow coastal plains that quickly give way to steep, undulating hills and valleys covered in dense rainforest.
The island is transected by several small rivers and streams, most notably the Galathea River and the Alexandra River, which flow into the sea creating estuarine ecosystems rich in mangroves. The highest elevation on Great Nicobar is Mount Thullier, which rises to 642 meters (2,106 feet) above sea level, located to the north of Campbell Bay. The 2004 earthquake altered the local topography significantly, causing the southern part of the island (around Indira Point) to subside by several meters, permanently inundating former coastal plains.
