Kingdom of Champasak
The river was an 18th-century migration route for the re-peopling of the Khorat Plateau by ethnic Lao people from the left (east) bank of the Mekong resettling on the right bank. This began in 1718 when the first king of the left bank Kingdom of Champasak, King Nokasad, sent a group of some 3,000 subjects led by an official in his service to found the first settlement in the Chi River valley—and indeed anywhere in the interior of the Khorat Plateau—Muang Suwannaphum in present-day Roi Et Province (a history recorded and remembered, largely in terms of the struggle to expand wet-rice cultivation in the river valley). Their descendants are now regarded as a separate ethnic group from the Lao to the north and the central Thai to the southwest.