The border starts in the north at the tripoint with Laos at the confluence of the Kok and Mekong Rivers and, after briefly following the Kok and then the Sai, then proceeds overland to the west via a series of irregular lines through the Daen Lao Range, before turning to the south-west and joining the Salween River. The border follows the Salween and then Moei River southwards, before leaving it and proceeding southwards overland through the Dawna Range and Bilauktaung Range (collectively these mountains form the Tenasserim Hills). The border continues southwards down the Malay Peninsula, almost cutting Thailand in two at Prachuap Khiri Khan, before reaching the Isthmus of Kra and the Kraburi River, which it then follows out via a wide estuary to the Andaman Sea. The maritime boundary then follows coordinates marked by the countries' continental shelf delimitation agreement towards the tripoint with India, which controls the Andaman and Nicobar Islands.