Map of Laos
Its location has often made it a buffer between more powerful neighboring states, as well as a crossroads for trade and communication. Migration and international conflict have contributed to the present ethnic composition of the country and to the geographic distribution of its ethnic groups. Most of the western border of Laos is demarcated by the Mekong River, which is an important artery for transportation. The Dong falls at the southern end of the country prevent access to the sea, but cargo boats travel along the entire length of the Mekong in Laos during most of the year. Smaller power boats and pirogues provide an important means of transportation on many of the tributaries of the Mekong.