<P> The eastern border with Vietnam extends for 2,130 kilometres , mostly along the crest of the Annamite Chain , and serves as a physical barrier between the Chinese - influenced culture of Vietnam and the Indianized states of Laos and Thailand . These mountains are sparsely populated by tribal minorities who traditionally have not acknowledged the border with Vietnam any more than lowland Lao have been constrained by the 1,754 - kilometre Mekong River border with Thailand . Thus , ethnic minority populations are found on both the Laotian and Vietnamese sides of the frontier . Because of their relative isolation , contact between these groups and lowland Lao has been mostly confined to trading . </P>
<P> The eastern border with Vietnam extends for 2,130 kilometres , mostly along the crest of the Annamite Chain , and serves as a physical barrier between the Chinese - influenced culture of Vietnam and the Indianized states of Laos and Thailand . These mountains are sparsely populated by tribal minorities who traditionally have not acknowledged the border with Vietnam any more than lowland Lao have been constrained by the 1,754 - kilometre Mekong River border with Thailand . Thus , ethnic minority populations are found on both the Laotian and Vietnamese sides of the frontier . Because of their relative isolation , contact between these groups and lowland Lao has been mostly confined to trading . </P>
what natural feature forms most of the border between laos and thailand
what natural feature forms most of the border between laos and thailand
the Annamite Chain
the Annamite Chain