The Arghandab is a river in Afghanistan, about 400 km (250 mi) in length. It rises in Ghazni Province, west of the city of Ghazni, and flows southwest, passing near the city of Kandahar, before joining the Helmand River 30 km (19 mi) below the town of Grishk. In its lower course, it is much used for irrigation, under the control of the Helmand and Arghandab Valley Authority, and the valley is cultivated and populous; yet the water is said to be somewhat brackish. It is doubtful whether the ancient Arachotus is to be identified with the Arghandab or with its chief confluent the Tarnak, which joins it on the left 50 km (31 mi) southwest of Kandahar. The Tarnak, which flows south of Kandahar, is much shorter and less copious.

Kandahar is a city in Afghanistan, located in the south of the country on the Arghandab River, at an elevation of 1,010 m (3,310 ft). It is Afghanistan's second largest city after Kabul, with a population of about 614,118. It is the capital of Kandahar Province and the centre of the larger cultural region called Loy Kandahar. Kandahar is the founding city and spiritual center of the Taliban. Despite the capital of Afghanistan being Kabul, where the government administration is based, Kandahar is the seat of power in Afghanistan as the supreme leader and his spiritual advisers are based there. Kandahar has therefore been called the de facto capital of Afghanistan, though the Taliban maintain Kabul is the capital.