Iran–Iraq border

The Iran–Iraq border runs for 1,599 km (994 mi) from the tripoint with Turkey in the north down to the Shatt al-Arab (known as Arvand Rud in Iran) waterway and out to the Persian Gulf in the south.

[4][5][6][7] The Zuhab treaty stipulated that the boundary between the two empires would run between the Zagros Mountains and the Tigris River, though a precise lines was not drawn at that time.

[8] The four-nation boundary commission then surveyed the border on the ground and demarcated it with pillars, producing a detailed series of map depicting the confirmed frontier.

As a result of the secret 1916 Anglo-French Sykes–Picot Agreement Britain gained control of the Ottoman Vilayets of Mosul, Baghdad and Basra, which it organised into the mandate of Iraq in 1920.

[8] The border was challenged by Iran in 1934 at the League of Nations, with the validity of both the Treaty of Erzurum and the Constantinople Protocol being called into question.

[16] A peace agreement was signed on 6 March 1975 in Algiers in which both parties pledged to further demarcate the border, both on land and in the Shatt al-Arab, based upon the Erzurum Treaty and Constantinople Protocol.

[8] Relations soured once again in 1979, as Saddam Hussein formally took office and the Shah of Iran was overthrown in the Islamic Revolution and replaced by a Shi'ite theocracy under Ayatollah Ruhollah Khomeini.

[21] Almost the entire ground war was fought in close proximity to the international boundary, though the conflict resulted in stalemate and following the end of fighting no changes to the border were made.