The Mekong River running through the Indo-China Peninsula is the representative mega-river in Southeast Asia. The basin originate in Tibetan mountains of China, and includes other five countries, Myanmer, Laos, Thailand, Cambodia, and Vietnam.

The area of the Mekong River is about 795,000km², and the extent corresponds to more than two-times of Japanese land area. The main stream length is said 4,800km, and this long distance had prevented any expedition done by colonialist in modern times.

Ecology in the basin is extremely rich including many endangered species. The bio-diversity in the Mekong River basin is the second richest in the world following The Amazon. The natural resources are also rich, especially freshwater all through the basin.

The Mekong Countries or regions are poor area including the poorest countries. In the downstream basin against China border, called Lower Mekong(LM), over 100 ethnic minorities are living, and one-third of them faces severe condition in their income of under few dollars per day.