The Mekong River and its 15 tributaries make up a total of 2,400 km of waterways, but only about one third of these are navigable. 70% of the country is mountainous. In the south, the Annamite mountains reach 2,600m in height. The Khammouanne plateau in the centre of the range is mass of limestone karst. At the south of the range is the Bolaven Plateau. The north of Laos is made of steep sloped mountain ranges with the highest mountain in the country at 2820m in Xiang Khouang province. Over half of Laos is forest.

PEOPLE
There are 68 official ethnic groups in Laos, belonging to three main groups.

Lao Loum - Lao, or Lao Loum consists of about half of the poulation. The Lao Loum or lowland lao people live in the Mekong river valley and its tributaries. The Lao Loum cultivate and eat wet, or sticky rice, and generally practice Theravada Buddhism. Lao Loum are a subgroup of the Austro-Thai people and speak the Lao language. The Lao Loum women wear the traditional sinh - the wraparound sarong. Lao Tai are closely related to the Lao Loum and are officially classified in that group. The Lao Tai are more tribal than the Lao Loum and cultivate both wet rice and dry mountain rice. Lao Tai traditionally practice slash and burn agricultural methods. The Lao Tai on the whole have not converted to either Christianity or Buddhism and retain their animist beliefs. Lao Tai are further subdivided into sub groups by the colour of their traditional clothing, ie Black, White, Red Tai.

Lao Theung are the largest hilltribe group, with 45 subgroups. The Lao Theeung are semi nomadic and of Mon-Khmer origin. They live on mountain slopes, between 300 and 900m altitude and practice slash and burn agriculture. The Khamu subgroup is found in the north and grow mountain rice, cotton, coffee and tobacco. The Tin subgroup is found in Sayabouli province - they are hunters and do not use metal tools, using only wood and bamboo. The Akha and Alak subgroups live in the south in the Boloven plateau.

Lao Sung or High Lao live in the high mountains of the north. Main groups are the Hmong and the Mien. Hmong are divided into Black, Red, White and Striped, according to their clothing. The Hmong raise cattle, pigs and chickens and generally survive on a barter economy. The Mien have a similar language to the Hmong and are known for their silver craftsmanship. Smaller hilltribe groups include the Lisu, Lahu and Lolo.

As well as the four main groups, Laos also has a number of Chinese, mainly living in the cities as well as ethnic Vietnamese, Cambodians, Burmese and Thai, In Vientiane there are also a small number of southern Asians.