The Limes Mauretaniae was a portion of a 4,000-kilometre (2,500 mi) Roman fortified border (limes) in Africa approximately 100 kilometres (62 mi) south of the modern day Algiers.

Stretching between Auzia (Sour El-Ghozlane, Algeria) and Numerus Syrorum (Maghnia, Algeria), it was a portion of the North African border fortification and security line of the Roman Empire which reached from the Atlantic coast to the Limes Tripolitanus in Tunisia.

In Roman North Africa there were no continuous border fortifications such as Hadrian's Wall in Britain. The transitions on the Limes Africanus between Roman territory and the free tribal areas were fluid and were monitored only by the garrisons of a few outposts. Their security tasks were further complicated by long communication lines and the lack of a clear border. The greatest danger was posed by the nomadic Berber tribes, which carried on sporadic warfare with Rome. The chain of forts was primarily intended to mark the Roman domain. In many areas, the system also served to control and channel the migratory movements of nomadic tribes or peoples, including the monitoring and reporting of their activities, and as a customs border. This Limes was therefore not so much a military border security system, but rather a monitored economic border with the free nomadic peoples and hill tribes. The Limes could not have withstood a coordinated military attack.

During his civil war Julius Caesar defeated the partisans of Pompey at the Battle of Thapsus in 46 BC. After the battle the previously independent kingdom of Numidia, whose king, Juba I had sided with Pompey, was divided. Part of it was assigned to the Kingdom of Mauritania, and the other was added to the Roman province of Africa. The Kingdom of Mauritania was founded in 33 BC and bequeathed to Rome by King Bocchus II. The kingdom was initially under direct Roman rule. In 25 BC Augustus appointed Juba II as ruler of the client kingdom, but he did nothing to pacify the hinterland. In 23 AD his son Ptolemy succeeded him and put down an uprising against Rome. When Ptolemy visited Rome in 40 AD, however, Caligula had him murdered, and annexed the kingdom. The revolt that erupted was suppressed in 44 AD. Claudius divided the territory of the former kingdom into the provinces Mauretania Caesariensis, with its capital at Colonia Claudia Caesariensium Iol, now Cherchell, and Mauretania Tingitana, with its capital initially at Volubilis, and later at Tingis, today's Tangier.

In the African provinces, there was frequent unrest and uprisings during Roman rule. In 238 AD the governor of Africa, Gordian I, and his son Gordian II (as co-regent) were proclaimed against their will by the Roman Senate as the counter-emperor to Emperor Maximinus Thrax. However, their troops were defeated by the Legio III Augusta. Under Emperor Diocletian, the new province of Mauretania Sitifensis, named after its capital Sitifis (now Sétif), was separated from Mauretania Caesariensis.

In the 5th century, both provinces fell to the Vandals. Parts of Tingitana, Caesariensis, and Sitifensis were recaptured by the Byzantine Empire after the annihilation of the Vandal Kingdom by the Byzantine general Belisarius in the 6th century. Islamic expansion put an end to the rule of Byzantium in the 7th century.

The North African Limes protected the provinces which stretched about 90 to 400 kilometres (56 to 249 mi) inland from the Mediterranean. The geography of the provinces of Mauretania Caesariensis and Mauretania Tingitana was roughly divided into a variable-width coastal strip, followed by some very fertile mountain regions or river valleys, fading gradually into a steppe and desert steppe border area and mountain regions. The inhabitants of Mauritania, particularly in the Tingitana, were probably semi-nomadic hill tribes related to the Iberians.

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 400 kilometres (250 mi) to only around 95 kilometres (59 mi). 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.