Hodh Ech Chargui (, "Eastern Basin Region") is a large region in eastern Mauritania, with an area of 182,700 km2. Its capital is Néma, but the largest town, in Bassiknou Department, is Fassala (or Vassale) at the extreme southeast of Mauritania, with 65,927 inhabitants at the 2013 census. The region borders the Mauritanian regions of Adrar, Tagant and Hodh El Gharbi to the west and Mali to the east and south. The Aoukar basin, which formerly gave name to a greater region, is located in the western part of Hodh Ech Chargui.