(between the rivers), the entire country between the two rivers, the Tigris and the Euphrates. This is a tract nearly 700 miles long and from 20 to 250 miles broad, extending in a southeasterly direction from Telek to Kurnah. The Arabian geographers term it “the Island,” a name which is almost literally correct, since a few miles only intervene between the source of the Tigris and the Euphrates at Telek. But the region which bears the name of Mesopotamia, par excellence, both in Scripture and in the classical writers, is the northwestern portion of this tract, or the country between the great bend of the Euphrates, lat. 35 degrees to 37 degrees 30′, and the upper Tigris. We first hear of Mesopotamia in scripture as the country where Nahor and his family settled after quitting Ur of the Chaldees (Genesis 24:10). Here lived Bethuel and Laban, and hither Abraham sent his servants to fetch Isaac a wife. Hither too, a century later, came Jacob on the same errand, and hence he returned with his two wives after an absence of twenty-one years. After this we have no mention of Mesopotamia till the close of the wanderings in the wilderness (Deuteronomy 23:4). About half a century later we find, for the first and last time, Mesopotamia the seat of a powerful monarchy (Judges 3:8). Finally, the children of Ammon, having provoked a war with David, “sent a thousand talents of silver to hire them chariots and horsemen out of Mesopotamia, and out of Syria-maachah, and out of Zobah” (1 Chronicles 19:6). According to the Assyrian inscriptions Mesopotamia was inhabited in the early times of the empire by a vast number of petty tribes, each under its own prince, and all quite independent of one another. The Assyrian monarchs contended with these chiefs at great advantage, and by the time of Jehu had fully established their dominion over them. On the destruction of the Assyrian empire, Mesopotamia seems to have been divided between the Medes and the Babylonians. The conquests of Cyrus brought it wholly under the Persian yoke, and thus it continued to the time of Alexander. Since 1516 it has formed a part of the Turkish empire. It is full of ruins and mounds of ancient cities, some of which are now throwing much light on scripture.
Smith's Bible Names Dictionary (1866)