The Trans-Sahara Highway or TAH 2, formally the Trans-Saharan Road Corridor (TSR), and also known as the African Unity Road, is a transnational infrastructure project to facilitate trade, transportation, and regional integration among six African countries: Algeria, Chad, Mali, Niger, Nigeria, and Tunisia. It runs roughly 4,500 km north to south across the Sahara desert from Algiers, Algeria on the Mediterranean coast of North Africa to Lagos, Nigeria on the Atlantic coast of West Africa; subsequently, it is sometimes known as the Algiers–Lagos Highway or Lagos–Algiers Highway.