Irnina canal

The geography of Mesopotamia, encompassing its ethnology and history, centred on the two great rivers, the Tigris and Euphrates. While the southern is flat and marshy, the near approach of the two rivers to one another, at a spot where the undulating plateau of the north sinks suddenly into the Babylonian alluvium, tends to separate them still more completely. In the earliest recorded times, the northern portion was included in Mesopotamia; it was marked off as Assyria after the rise of the Assyrian monarchy. Apart from Assur, the original capital of Assyria, the chief cities of the country, Nineveh, Kalaḫ and Arbela, were all on the east bank of the Tigris. The reason was its abundant supply of water, whereas the great plain on the western side had to depend on streams flowing into the Euphrates.

Mesopotamia means "(Land) between two rivers" in ancient Greek. The oldest known occurrence of the name Mesopotamia dates to the 4th century BCE, when it was used to designate the land east of the Euphrates in north Syria. In modern times it has been more generally applied to all the lands between the Euphrates and the Tigris, thereby incorporating not only parts of Syria but also almost all of Iraq and southeastern Turkey. The neighboring steppes to the west of the Euphrates and the western part of the Zagros Mountains are also often included under the wider term Mesopotamia. A further distinction is usually made between Upper or Northern Mesopotamia and Lower or Southern Mesopotamia.Upper Mesopotamia, also known as the Jazirah, is the area between the Euphrates and the Tigris from their sources down to Baghdad. Lower Mesopotamia is the area from Baghdad to the Persian Gulf. In modern scientific usage, the term Mesopotamia often also has a chronological connotation. In modern Western historiography of the region, the term "Mesopotamia" is usually used to designate the area from the beginning of time, until the Muslim conquest in the 630s, with the Arabic names Iraq and Jazirah being used to describe the region after that event.

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