In medieval history, Iraq (Arabic: العراق al-ʿIrāq) was the area comprising the lower parts of Mesopotamia, being roughly equivalent in size and shape to the ancient region of Babylonia.
[1] It was bounded to the northwest by al-Jazira, to the north by Adharbayjan (the Sassanid Aturpatakan), to the northeast by al-Jibal, to the east by al-Ahwaz, to the southeast by the Sea of Fars (the Persian Gulf), and to the southwest by the desert of Arabia.
[3] After Ziyad's death the two towns were again separately administered, but subsequent caliphs were to repeat the combination and from the reign of 'Abd al-Malik ibn Marwan on, Iraq was usually in the hands of a single governor.
In addition to Iraq itself, he was frequently granted the responsibility for the provinces of the empire that had originally been conquered with Basran or Kufan troops, including al-Ahwaz, al-Jibal, Fars, Kerman, Khurasan, Sijistan, Makran, al-Sind, and Jurjan.
[9] Following their victory over the Umayyads, the Abbasids abolished the governorship of Iraq and resumed the practice of appointing separate governors to the individual districts of the region.