The Mekong River is one of the world's great rivers and its delta is one of the world's largest. The Mekong originates high in the Tibetan plateau, flowing 4500km through China, between Myanmar and Laos, through Laos, along the Laos-Thailand border, and through Cambodia and Vietnam on its way to the South China Sea.

At Phnom Penh (Cambodia), the Mekong River splits into two main branches: the Hau Giang (Lower River, also called the Bassac River), which flows via Chau Doc, Long Xuyen and Can Tho to the sea; and the Tien Giang (Upper River), which splits into several branches at Vinh Long and empties into the sea at five points. The numerous branches of the river explain the Vietnamese name for the Mekong: Song Cuu Long (River of Nine Dragons).