The Greater Mekong Subregion (GMS) is made up of Cambodia, the Peoples Republic of China (PRC, specifically Yunnan Province and Guangxi Zhuang Autonomous Region), Lao Peoples Democratic Republic (Lao PDR), Myanmar, Thailand, and Viet Nam.

Location of the Mekong Delta region within VietnamThe Mekong Delta (Vietnamese: đồng bằng sông Cửu Long “Nine Dragon river delta”) is the region in southwestern Vietnam where the Mekong River approaches and empties into the sea through a network of distributaries. The Mekong delta region encompasses a large portion of southeastern Vietnam of 39,000 square kilometres (15,000 sq mi).[1] The size of the area covered by water depends on the season.

Greater Mekong Subregion (GMS) Environment Operations Center (EOC) was established in early 2006 to serve as the information and knowledge clearing house for environmental management in the Greater Mekong Subregion (GMS) and is responsible for facilitating the timely and effective implementation of the GMS Core Environment Program (CEP).

The Greater Mekong Subregion (GMS) consists of Cambodia, China (Yunnan & Guanxi Provinces), Laos, Myanmar, Thailand and Vietnam.

Balls of light are observable from time to time rising from the waters surface in the stretch of the river near Vientiane or Nong Khai. These are sometimes referred to as Naga fireballs. The locals attribute the phenomenon to Phaya Naga, Mekong Dragons.

The headwaters of the Mekong in Zadoi County, Qinghai, China, are protected in Sanjiangyuan National Nature Reserve. The name Sanjiangyuan means the Sources of the Three Rivers; the reserve also includes the headwaters of the Yellow River and the Yangtze.

Recently there are two larg bridges are built in Yunnan Province,China. They are Mangjiedu Bridge in Xiaowan Hydropower Station and Xiyi Lancang-Mekong River Grand Bridge in Lincang City.

The first European to encounter the Mekong was the Portuguese Antonio de Faria in 1540; a European map of 1563 depicts the river, although even by then little was known of the river upstream of the delta. European interest was sporadic: the Spaniards and Portuguese mounted some missionary and trade expeditions, while the Dutch Gerrit van Wuysthoff led an expedition up the river as far as Vientiane in 1641–42.

A number of dams have already been built on the rivers tributaries, notably the Pak Mun dam in Thailand. This has been criticised on grounds of cost as well as damage to the environment and to the livelihoods of affected villagers, though none have been built on the main part itself.

The estimated hydropower potential of the lower Mekong Basin (i.e. excluding China) is 30,000 MW, while that of the upper Mekong Basin is 28,930 MW. In the lower Mekong, more than 3,235 MW has been met through facilities built largely over the past ten years, while an additional 3,209 MW are currently under construction. An additional 134 projects are planned for the lower Mekong, which will effectively exhaust the river’s hydropower generating capacity.