Istakhr was an ancient city located five kilometers north of Persepolis in Fars province, Iran.
Istakhr first appears in history as an Achaemenid city. It gained its importance not only from its close association with Persepolis: it also commanded the western end of an ancient caravan-route that ran from the Indus Valley via Kandahar and Drangiana to Persia.
The city temporarily became the capital of the Sasanian Empire during the reign of Ardashir I (r. 224–242) before the capital was moved to Ctesiphon, in Mesopotamia.