Arachosia is the Hellenized name of an ancient satrapy in the eastern part of the Achaemenid, Seleucid, Parthian, Greco-Bactrian, and Indo-Scythian empires. Arachosia was centred on Arghandab valley in modern-day southern Afghanistan, and extended east to as far as the Indus River in modern-day Pakistan. The main river of Arachosia was called Arachotós, now known as the Arghandab River, a tributary of the Helmand River. The Greek term "Arachosia" corresponds to the Aryan land of Harauti which was around modern-day Helmand. The Arachosian capital or metropolis was called Alexandria or Alexandropolis and lay in what is today Kandahar in Afghanistan. Arachosia was a part of the region of ancient Ariana.