National Highway 3 is actually an international road, leading from Hanoi, through Thai Nguyen and Bac Kan Provinces, to Cao Bang Province and its border gate into China. It connects to a number of highways in Hanoi, especially the main national north-south Highway 1, which goes through Saigon/Ho Chi Minh City to the Mekong Delta. Highway 1 intersects Highway 5 to Haiphong.