In March 1975, subsequent to discussions at an OPEC meeting, Iran and Iraq agreed to meet and negotiate their dispute over borders and water and navigation rights. This meeting resulted in the Algiers accord below, and in a subsequent treaty signed June 13, 1975. During the convocation of the OPEC Summit Conference in the Algerian capital and upon the initiative of President Houari Boumedienne, the Shah of Iran and Saddam Hussein (Vice-Chairman of the Revolution Command Council) met twice and conducted lengthy talks on the relations between Iraq and Iran. The thalweg, meaning the median course of the Shatt-El-Arab waterway, was designated as the border. The agreement caused the Shah of Iran to withdraw Iranian support for the Kurdish rebellion, which thereupon collapsed.
Less than six years after signing the treaty, Iraq attacked Iran to invade the border lands. The main points of the dispute concerned the Shatt El Arab, a waterway that is Iraq’s only outlet to the sea, as well disputed islands and territories. In part, the dispute arose because of the shifting course of the Shatt El Arab. Even after the war, the disputes have not been totally resolved. More Here