Irak-Arabi, Or Irak-I-Arabi, the Arabic name, and a common designation among orientalists, for the S. E. portion of Asiatic Turkey, and some adjoining territory to the east. It corresponds to ancient Babylonia and Elam or Susi-ana, and includes the pashalic of Bagdad, excepting the northern portion, and the S. W. frontier land of Persia, principally Khuzistan. It comprises therefore the alluvium at the head of the Persian gulf as far north as about lat. 33°, in the neighborhood of Hit on the Euphrates, and between the Syrian desert on the west and the mountain ranges of Kurdistan, Luristan, and Khuzistan on the east. This alluvium is said to increase with extraordinary rapidity, and it is supposed that its growth was still more rapid in ancient times, and that when the first Chaldean monarchy was established the Persian gulf reached 120 or 130 m. further inland than at present. Raw-linson says of this region that nothing is more remarkable than its featureless character. It is a dead level, broken only by single solitary mounds, the remains of ancient temples or cities, and by long lines of embankment marking the course of ancient and recent canals.

Near the streams and canals are lands of great fertility, but the rest, except in early spring, is almost as parched and arid as the most desolate districts of Arabia. The principal rivers are the Tigris and Euphrates. A wide and deep channel, branching off near Hit, skirting the Syrian desert, and entering the Persian gulf by a separate mouth, was probably the ancient western limit. The part east of the Tigris is the most fertile, and forms in a large measure the storehouse of the remainder of this district. Nearly all of Turkish Khuzistan, however, is but little cultivated, though its soil has every characteristic of luxuriant fertility. The climate and products of the region are mainly described in the articles upon the two principal towns, Bagdad and Bassorah.