Because of its meridian structure and even before the loss of the territories on the right bank of the Mekong to Thailand, Lan Xang never had centralized management. In the 17th and 18th centuries the kingdom was composed of three entities: the royal territory at Vientiane, surrounded by two others—Luangphrabang in the north and Champassack in the south. It maintained close relations with the Phuan kingdom of Xiengkhuang in the North-East, and with the two confederations of principalities in the north (Sip Song Phan Na to the west and Sip Song Chau Tai to the east). This organization into three territories distributed along the Mekong dated from its founding in the 14th century; the capital and royal territory were   moved   from Luangphrabang to Vientiane in 1553. This legacy is still evident today, but the three entities need to be redefined.

The meridian partition between the zones controlled by the Pathet Lao, which was extended at the expense of that controlled by the royal government between 1963 and 1973, gave a new territorial form to the contrast between the Mekong Valley and the mountainous interior. This constitutive element of the Laotian territory explains the predominance of an organization in parallel belts.