Lower Mesopotamia^[1][2] is ahistorical region ofMesopotamia. It is located in thealluvial plain ofIraq from theHamrin Mountains to theFaw Peninsula near thePersian Gulf.

In the Middle Ages it was also known as theSawad and al-Jazira al-sflia ("Lower Jazira"), which strictly speaking designated only the southern alluvial plain,^[3] andArab Iraq, as opposed toPersian Iraq, theJibal.^[4] Lower Mesopotamia was home toSumer andBabylonia.^[5]

The medieval Arab geographers placed the northern border between Iraq andUpper Mesopotamia (theJazirah) in a line running fromAnbar on the Euphrates toTikrit on theTigris, although later it was shifted to a line running due west from Tikrit, thus including several towns on the Euphrates past Anbar into Iraq.^[6]

Analluvial plain begins north ofTikrit NearHamrin Mountains and extends to thePersian Gulf. Here theTigris andEuphrates lie above the level of the plain in many places, and the whole area is ariver delta interlaced by the channels of the two rivers and byqanat. Intermittentlakes, fed by the rivers in flood, also characterize southeastern Iraq. A fairly large area (15,000 km² or 5,800 sq mi) just above the confluence of the two rivers atal Qurnah and extending east of the Tigris beyond the Iranian border is marshland, known asLake Hammar, the result of centuries of flooding and inadequate drainage. Much of it is permanent marsh, but some parts dry out in early winter, and other parts become marshland only in years of great flood.

Because the waters of the Tigris and Euphrates above their confluence are heavilysilt-laden,irrigation and fairly frequent flooding deposit large quantities of silty loam in much of the delta area. Windborne silt contributes to the total deposit of sediments. It has been estimated that the delta plains are built up at the rate of nearly twenty centimeters in a century. In some areas, major floods lead to the deposit in temporary lakes of as much as thirty centimeters of mud.

The Tigris and Euphrates also carry large quantities ofsalts. These, too, are spread on the land by sometimes excessive irrigation and flooding. A highwater table and poor surface and subsurface drainage tend to concentrate the salts near the surface of the soil. In general, the salinity of the soil increases from Baghdad south to the Persian Gulf and severely limits productivity in the region south ofAmarah. Thesalinity is reflected in the large lake in central Iraq, southwest of Baghdad, known asLake Milh. There are two other major lakes in the country to the north of Lake Milh:Lake Tharthar andLake Habbaniyah.

• List of Umayyad governors of Iraq

• Le Strange, Guy (1905).The Lands of the Eastern Caliphate: Mesopotamia, Persia, and Central Asia, from the Moslem Conquest to the Time of Timur. New York: Barnes & Noble, Inc.OCLC 1044046.

• Articles with short description
• Short description matches Wikidata
• Mesopotamia
• Geography of the Middle East
• Historical regions of Iraq