Hai Van pass is approximately 20km long and 500m above sea level. It is on National Highway 1A, some 80km from the heart of Hue to the south and over 20km from the centre of Da Nang to the north, running across Bach Ma mountain which stretches from the Truong Son range to the sea, creating a natural boundary between Thua Thien-Hue province and Da Nang city.