Laos is a landlocked nation covering 236,800 square kilometers in the center of the Southeast Asian peninsula and it is surrounded by Myanmar, Cambodia, China, Thailand, and Vietnam. The country is divided into three distinct regions: mountains, plateaus and the plains. Around three-quarters of Laos are made of mountains and plateaus especially in the areas of the North and South-East. Northern Laos is dominated by rough mountains, jungles and agricultural areas. The plain region is located along the Mekong River and forms the other quarter of the country.
The Mekong River flows through almost 1,900 kilometers of the country from the North to the South and is the main geographical feature of Laos. Most of the western border of Laos is demarcated by the river and forms a natural border with Thailand for over 800 kilometers. The Mekong is an important artery for transportation.
The north is dominated by mountains that average 1,500 metres above sea level. The highest peak is the 2,800 metre Phou Bia in Xieng Khouang province. The Phou Luang (Annamite Chain) stretches from the southeast of the Phouane Plateau down to the Cambodian border. It has three large plateaux: Phouane Plateau in Xieng Khouang province, Nakai Plateau in Khammouane province, and Boloven Plateau in southern Laos, 1,000 m above sea level.
The plains region comprises large and small plains along the Mekong River. The largest of these is the Vientiane Plain, on the lower reaches of the Nam Ngum River. Also significant are the Savannakhet plain, on the lower reaches of the Se Bang Fai and Se Bang Hieng rivers, and the Champassak plain, which is on the Mekong River, stretching between the Thai and Cambodian borders. Blessed with fertile soil, these plains represent one quarter of the total area and are the “granaries” of the country.
The Lao PDR is criss-crossed by many rivers and streams. The Mekong River flows through 1,835 km of the country from north to south. Rivers and streams provide great potential for hydropower development. Over half of the power potential in the lower Mekong Basin is contained within Laos.
The Nam Ou river flows from Phonsaly to Luang Prabang for 448 km; the Nam Ngum runs 354 km from Xieng Khouang to Vientiane province; the Se Bang Hieng of Savannakhet province is 338 km long; the Nam Tha runs from Luang Namtha to Bokeo for 325 km; the Nam Sekong runs 320 km from Saravane and Sekong to Attopeu province; the Se Bang Fai runs between Khammouane and Savannakhet for 239 km; Oudomsay province’s Nam Beng covers 215 km; the Nam Sedong flows for 192 km between Saravane and Champassak; the Nam Selanong in Savannakhet runs for 115 km; the Nam Kading of Borikhamsay province is 103 km long; the Nam Khanh runs for 90 km between Huaphanh and Luang Prabang.