narrow coastal region, southeastern Myanmar (Burma), bordered to the east by Thailand and to the west by the Andaman Sea. The Mergui Archipelago, with more than 200 islands of varying sizes, fringes the western shore. Tenasserim is dominated by the Tenasserim Range, which reaches a height of 6,801 feet (2,074 m), and is bisected by the Great Tenasserim River, which flows south to the Andaman Sea. Swamp forests are found on the east coast. The Tenasserim plains to the north are drained also by short and rapid rivers, which enter the Gulf of Martaban. The ethnic composition of the area consists of Karens in the west and north, Thai in the south, and Burmans who speak a unique dialect of Burmese in the other areas
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