The Trans-Sahara Highway or TAH 2, formally the Trans-Saharan Road Corridor (TSR),[1] and also known as the African Unity Road,[2] is a transnational infrastructure project to facilitate trade, transportation, and regional integration among six African countries: Algeria, Chad, Mali, Niger, Nigeria, and Tunisia.

The TSR is one of the oldest and most complete transnational highways in Africa, having been proposed in 1962, with construction of sections in the Sahara starting in the 1970s.

[1] In addition to paving and widening existing roads, the corridor includes thousands of kilometres of cable as part of the "Trans-Saharan Fibre Optic Backbone", a multinational project to increase high-speed telecommunications across the region.

About half the highway, over 2,300 km, lies in Algeria and is mostly in good condition, with the newest sections south of Tamanrasset.

[6] The Cairo–Cape Town Highway (TAH 4) follows the Nile in the east, the previous long unpaved sections in Sudan, Ethiopia and Kenya have since been significantly improved.

Established during the French colonial era as a link between Algiers with Dakar to avoid what was then the Spanish Sahara on the Atlantic, it was closed in 1963.