The overall topography of Laos is hilly and mountainous with thick green forests. River valleys and an increasingly steep terrain front the mountainous landscape.
The highest point of Laos is Phou Bia whose summit peaks at 9,242 ft. (2,817 m). The lowest point is along the Mekong River at 229 ft. (70 m).
A very small percentage of Laos is farmable, and the limited flat areas (lower lands) are found in the south and along the Mekong River border with Thailand.
Dozens of rivers flow from the upper reaches of the mountains as tributaries of the Mekong, southeast Asia's most significant river.
The Mekong is the world's 12th-longest river and the 7th-longest in Asia. Its estimated length is 4,350 km (2,703 mi), and it drains an area of 795,000 km2 (307,000 sq mi).