Al-Dahnāʾ, great arc of reddish sandy desert, central Saudi Arabia, extending about 800 miles (1,300 km) southward from the northeastern edge of the desert Al-Nafūd to the northwestern borders of the desert Rubʿ al-Khali (the Empty Quarter). Thus, Al-Dahnāʾ links the great deserts of Saudi Arabia. It consists of seven major sand ridges, which are separated from one another by plains. It measures about 30 miles (48 km) in width and provides spring and winter pastures. Al-Dahnāʾ is crossed by roads connecting Kuwait with Al-Zilfī and Riyadh and connecting Riyadh with Hasa.