Iran–Turkmenistan border

It is 1,148 km (713 miles) in length and runs from the Caspian Sea to the tripoint with Afghanistan.

The border starts at the Caspian coast just to the south of the Turkmen town of Esenguly.

It then goes overland in an eastwards directions in a series of straight lines through barren salt flats for 50 km (31 mi) until reaching the Atrek river, the course of which it follows for 124 km (77 mi) to a point just south of the Turkmen village of Chat.

[2] It then continues overland across mountain ridges in a broadly south-eastern arc for 455 km (283 mi) to the vicinity of the Iranian village of Chahchaheh.

[2][4] Further small changes were made in the period 1954-57 when Iran and the USSR (as they now were) agreed to more clearly demarcate their common border, including the Atrek delta region which had since altered due to the shrinking of the Caspian Sea.