Geography Laos is a landlocked country covering 236,800 square kilometres making it about the same size as Ecuador or Great Britain. It comprises mostly mountains and plateaux. The Mekong River flows through western and southern regions and forms a natural border with Thailand and Myanmar. On its banks nestle most of Laos' important cities, such as the capital Vientiane and the former royal capital, Luang Prabang. Rugged mountains cover more than 75% of the country. The vegetation is diverse and rich comprising tropical and subtropical species, from mango and palms to hardwoods. About half the country is still covered with primary forests.