Pakse is the capital and most populous city of the southern Laotian province of Champasak. Located at the confluence of the Xe Don an…Pakse is the capital and most populous city of the southern Laotian province of Champasak. Located at the confluence of the Xe Don and Mekong Rivers, the district had a population of approximately 77,900 at the 2015 Laotian census.