Claim: Iraq borders other countries.

Shatt al-Arab -LRB- شط العرب , Bank of the Arabs -RRB- or Arvand Rud -LRB- اَروَندرود , Swift River -RRB- is a river in Basra Governorate of some 200 km -LRB- 120 mi -RRB- in length , formed by the confluence of the Euphrates and the Tigris in the town of al-Qurnah in the Basra Governorate of southern Iraq . The southern end of the river constitutes the border between Iraq and Iran down to the mouth of the river as it discharges into the Persian Gulf . The river is geopolitically significant because it forms a natural border between Iran and the Arab world -LRB- Iraq -RRB- . It varies in width from about 232 m at Basra to 800 m at its mouth . It is thought that the waterway formed relatively recently in geologic time , with the Tigris and Euphrates originally emptying into the Persian Gulf via a channel further to the west .   The Karun river , a tributary which joins the waterway from the Iranian side , deposits large amounts of silt into the river ; this necessitates continuous dredging to keep it navigable .   The area is judged to hold the largest date palm forest in the world . In the mid-1970s , the region included 17 to 18 million date palms , an estimated one-fifth of the world 's 90 million palm trees . But by 2002 , war , salt , and pests had wiped out more than 14 million of the palms , including around 9 million in Iraq and 5 million in Iran . Many of the remaining 3 to 4 million trees are in poor condition .   In Middle Persian literature and the Shahnama -LRB- written between c. 977 and 1010 AD -RRB- , the name اروند Arvand is used for the Tigris , the confluent of the Shatt al-Arab . Iranians also used this name specifically to designate the Shatt al-Arab during the later Pahlavi period , and continue to do so after the Iranian Revolution of 1979 .