Geography of Zabul Province

Sistān (), also known as Sakastān (, , current name: Zabol) and Sijistan (), is a historical region in south-eastern Iran, and extending across the borders of south-western Afghanistan, and south-western Pakistan. Mostly corresponding to the then Achaemenid region of Drangiana and extending southwards of the Helmand River not far off from the city of Alexandria in Arachosia. Largely desert, the region is bisected by the Helmand River, which empties into the Hamun Lake, located in Zabol, that forms part of the border between Iran and Afghanistan.