The Mekong River is the largest river in Southeast Asia, with a length of 4,350 km flowing through six countries: China, Myanmar, Thailand, Lao PDR, Cambodia, and Vietnam. The Mekong River Basin encapsulates a large area and can be defined into 7 physiographic regions: Tibetan Plateau, Three Rivers Area, Lancang Basin, Northern Highlands, Khorat Plateau, Tonle Sap Basin, and the Mekong Delta. The Tibetan Plateau, Three Rivers Area and Lancang Basin form the Upper Mekong Basin while the Northern Highlands, Khorat Plateau, Tonle Sap Basin and Mekong Delta make up the Lower Mekong Basin. Laos is situated within the Lower River Basin, which has a catchment of 25% of the MRB -- approximately 202,000 km2 of water. The region of Laos contains 35% of Mekong's total inflows.