Assaba () is a region in southern Mauritania, covering an area of 36,600 square km. It had a population of 325,897 at the 2013 Census. Its capital is Kifa. Other major cities/towns include Guerou. The region borders the Mauritanian regions of Brakna and Tagant to the north, the Mauritanian region of Hodh El Gharbi to the east, Mali to the south, and the Mauritanian regions of Gorgol and Guidimaka to the west. The Aoukar basin, which formerly gave name to the greater region, is located in the north and the east of the central part of Assaba.