The Hari River or Herat River or Tejen River or Harirud is a river flowing 1,100 kilometres (680 mi) from the mountains of central Afghanistan to Turkmenistan, where it forms the Tejen oasis and disappears in the Karakum Desert. In its lower course, the river forms a northern part of the border between Afghanistan and Iran, and a southeastern part of the border between Turkmenistan and Iran.

Turkmenistan is a country in Central Asia bordered by Kazakhstan to the northwest, Uzbekistan to the north, east and northeast, Afghanistan to the southeast, Iran to the south and southwest and the Caspian Sea to the west. Ashgabat is the capital and largest city. It is one of the six independent Turkic states. With a population of 6.5 million, Turkmenistan is the 35th most-populous country in Asia and has the lowest population of the Central Asian republics while being one of the most sparsely populated nations on the Asian continent.