The southernmost district of Burma and of the Tenasserim Division, extending on the mainland from the Myin-hmo-let-kat mountain (13°28´ N.) on the border of the Tavoy district in the north, to the mouth of the Pakchan river(9°58´ N.)and the Isthmus of Kra in the south, and including the islands of the Mergui Archipelago from Tavoy Island to the Aladdin Isles in 9°38´ N. On the east it is conterminous with Siam, and at one point, in 99°40´ E., the gulf of Siam is only ten miles away. On the west the islands stretch out as far as 97º30´ E. As regards the islands off the mouth of the Pakchan river the line of demarcation between the British and Siamese islands runs to the south-west from the southernmost point of Victoria Island and passes to the north of Saddle Island and Delisle Island and to the south of Auriol Island and Cbristie's Islands. The islands to the south of that line are Siamese and those to the north are British. The total area is 9,789 square miles.