Located between 6° and 14° North Latitude and 92° and 94° East Longitude lie the Andaman and Nicobar Islands, a union territory in India. It consists of two groups of islands. The islands located north of 10° north latitude are known as Andaman while islands located south of 10° north latitude are called Nicobar.
more than 300 islands make up the Andamans. North, Middle, and South Andaman, known collectively as Great Andaman, are the main islands; others include Landfall Island, Interview Island, the Sentinel Islands (where the Sentinelese tribes live), Ritchie’s Archipelago, and Rutland Island.
The 10 degree channel which is about 145 kms long seperates Little Andaman in the south from the Nicobar Islands.
The Nicobars consist of 19 islands. Among the most prominent are Car Nicobar in the north; Camorta, Katchall, and Nancowry in the centre of the chain; and Great Nicobarin the south. About 90 miles to the southwest of Great Nicobar lies the northwestern tip of Sumatra, Indonesia.
Both the Andaman and Nicobar groups are formed by the above-sea extensions of submarine ridges of mountains and are a part of a great island arc. The highest peak is 2,418 feet at Saddle Peak on North Andaman, followed by Mount Thullier at 2,106 feet on Great Nicobar and Mount Harriet at 1,197 feet on South Andaman. Barren island, the only known active Volcano in south asia lies in the Andaman sea. In the late 20th and early 21st centuries, there were volcanic eruptions on Barren Island.
Formed of sandstone, limestone, and shale of Cenozoic age (i.e., formed during the past 65 million years), the terrain of the Andamans is rough, with hills and narrow longitudinal valleys. Flat land is scarce and is confined to a few valleys, such as the Betapur on Middle Andaman and Diglipur on North Andaman. Perennial rivers are few.
The terrain of the Nicobar is more diverse than that of the Andamans. Some of the Nicobar Islands, such as Car Nicobar, have flat coral-covered surfaces with offshore coral formations that prevent most ships from anchoring. Other islands, such as Great Nicobar, are hilly and contain numerous fast-flowing streams. Great Nicobar is the only island in the territory with a significant amount of fresh surface water.
The climate of the Andaman and Nicobar Islands is tropical but is moderated by sea breezes. Temperatures typically rise from about 23 °C into about 30 °C. The territory receives roughly about 120 inches of rain annually, brought mainly by the southwest monsoon, which blows from May through September, and by the tropical cyclones that follow in October and November.