Covering an area slightly larger than Great Britain, landlocked Laos shares borders with China, Myanmar, Thailand, Cambodia and Vietnam. Rivers and mountains dominate, folding the country into a series of often-spectacular ridges and valleys, rivers and mountain passes, extending westward from the Lao-Vietnamese border.

Mountains and plateaus cover well over 70% of the country. Running about half the length of Laos, parallel to the course of the Mekong River, is the Annamite Chain, a rugged mountain range with peaks averaging between 1500m and 2500m in height. Roughly in the centre of the range is the Khammuan Plateau, a world of dramatic limestone grottoes and gorges where vertical walls rise hundreds of metres from jungle-clad valleys At the southern end of the Annamite Chain, covering 10,000 sq km, the Bolaven Plateau is an important area for the cultivation of high-yield mountain rice, coffee, tea and other crops that flourish in the cooler climes found at these higher altitudes.

The larger, northern half of Laos is made up almost entirely of broken, steep-sloped mountain ranges. The highest mountains are found in Xieng Khuang Province, including Phu Bia, the country's highest peak at 2820m, though this remains off-limits to travellers for now. Just north of Phu Bia stands the Xieng Khuang plateau, the country's largest mountain plateau, which rises 1200m above sea level. The most famous part of the plateau is the Plain of Jars an area somewhat reminiscent of the rolling hills of Ireland - except for the thousands of bomb craters. It's named for the huge prehistoric stone jars that dot the area, as if the local giants have pub-crawled across this neighbourhood and left their empty beer mugs behind.

Much of the rest of Laos is covered by forest most of which is mixed deciduous forest. This forest enjoys a complex relationship with the Mekong and its tributaries, acting as a sponge for the monsoon rains and then slowly releasing the water into both streams and the atmosphere during the long dry season.