Arachosia /ærəˈkoʊsiə/ 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 the Arghandab valley in modern-day southern Afghanistan, although its influence extended east to as far as the Indus River in modern-day Pakistan. The main river of Arachosia was called Arachōtós, now known as the Arghandab River, a tributary of the Helmand River. The Greek term "Arachosia"