The eastern border of the province of Mauretania Caesariensis (identical to the eastern border of the later province of Sitifensis) ran approximately on a line west of Cape Bougaroun on the Ampsaga River to the east end of the Chott el Hodna and further west into the steppe landscape. This line also separated the sedentary population from the nomads, and formerly formed the border of the area dominated by Carthage. The southern border approached the coast along the northern slope of the Tell Atlas in the transition from Numidia to Mauretania Caesariensis. The Roman-dominated area thus shrank from a width of around to only around . The more north-facing border in Mauretania Caesariensis was roughly in line with the precipitation limit required for agriculture. The Roman armed forces, which were only weakly represented here, were also decisive for the initial limitation of the territory.