Nakhon Champassak was one of the provinces created as a result of the Franco-Thai War when Vichy France agreed to cede Meluprey and Thala Barivat province from Cambodia and the cis-Mekong part of Champasak Province from Laos to Thailand. The two sections were merged to form Nakhon Champassak Province. After World War II ended with the victory of the Allies, the post-war administration in France threatened to block Axis-aligned Thailand's admission into the newly formed UN. Finally in 1946 this province was dissolved and returned to France.