SEISTAN, the ancient Sakastane ("land of the Sakae"), an extensive border district between Persia and Afghanistan, situated in most part between 29° o' and 32° o' N., and 61° o' and 62° 3o' E. Its area, some 1 oo m. in extreme length and breadth, covers about 7,00o sq.m. about two-fifths of which lies in Persia and three-fifths in Afghanistan. The total population was estimated at 205,000 in 1906.
A physical feature of this region of Asia is that none of the rivers flow to the sea, but discharge into great inland depressions— the Seistan depression being one—of which the general level is about 1,400-1,700 ft. above the sea. Regarded as a whole the Seistan depression, or Hamun, into which the rivers here discharge themselves, consists of two extensive lagoons, formed respectively by the Harud Rud and the Farah Rud (both coming from the north), and by the Helmund river and Khash Rud (coming re spectively from the south and east). South of these lagoons extends a tract of country covered with reeds called the Naizar. When the rivers are in flood the two lagoons become united and the inundation covers the Naizar also. A further tract then also becomes overflowed, so that a great lake is formed which, lastly, discharges its redundant waters, through a course called the Shela (or Shelag), into a depression called the Gawd i Zarih.
The population consists chiefly of Tajiks, but Baluchis and Qainis, descendants of the ancient' rulers of the land, have also established themselves; and Nadir Shah forced some nomad tribes of Shiraz to emigrate to Seistan.
Politically, Seistan is divided between Persia and Afghanistan by a theoretical boundary line fixed by Commissions appointed to examine the question in 1872 and 1903-5. This line runs from the Kuh i Malik Siyah mountain, on the Perso-Afghan frontier, roughly north-east to Band i Seistan on the Helmund, thence northward to the Naizar reed beds on the Hamun shore, whence it turns westward to Siyah Kuh. The part falling to Persia west of this line is usually known as "Seistan Proper" and that on the east as "Outer Seistan."
The original chief town of Persian Seistan, Sihkuna, has been supplanted by Nasratabad (formerly Nasirabad), founded by the Amir of Qain about 1870, and locally known as Shahr-i-Seistan. Qain (q.v.) and Seistan together form a hereditary governorship, practically independent of the governor-general of Khurasan.
The trade outlets from Seistan proper are: (a) from Nasratabad southward to Duzdab (135 m.) and thence by rail to Nushki and Quetta ; (b) from Nasratabad to Birjand, where the route joins the Meshed-Duzdab motor road. Both roads are unmetalled but are passable for light motor traffic ; transport by caravan on the first takes 7-8 days to Duzdab, and on the second 14-15 days to Birjand. A project was under consideration in 1927 for a light railway from Duzdab to Seistan, for the transport of the wheat which is the special product of the district, to the Indian market.
Afghan Seistan comprises the land east of the frontier described above, and includes the Hamun i Puza (the more eastern of the two northern lagoons) up to Juwaim in the north ; the tract ex tends southward to the frontier of Persian Baluchistan, in which country lies the Gawd i Zarih lagoon. The capital is Khakansur, a small settlement on the Khash Rud, about 3o m. north-east of Nasratabad.
History.—The ancient Drangiana, or land of the Drangai, received the name of Sakastane after the country was conquered by the Sakae (Scythians) about 128 B.C. Certain references in the Avesta lead to the supposition that Seistan, in antiquity, was a principal seat of the Zoroastrian religion. In ancient and mediaeval times the name Sakastane denoted a larger area than the name now implies and possibly even included a great area towards the east up to Kandahar. Ardashir, the founder of the Sasanian dynasty, subjugated Sakastane, but during the Sasanian epoch the Sakae appear rather as allies than subjects.