Two great rivers run through Assyria, the Tigris and the Euhprates, and many lesser ones, the most important of which being the Upper Zab and Lower Zab, both tributaries to the Tigris. Strategically surrounding the Tigris and the two Zabs are the Assyrian cities of Nineveh, Ashur, Arbel, Nimrod and Arrapkha.
To the north and east of Assyria lie the Taurus and Zagros mountains. To the west and south lies a great, low limestone plateau. At the southern end of Assyria the gravel plains give way to alluvium deposited by the Tigris, and farther south there is insufficient rainfall for agriculture without irrigation. These two features create a geogrpahical boundary between Assyria and the neighboring land to the south.
To the south of Baghdad lies Babylon. There is a stark geographical distinction between Babylonia and Assyria. To quote Saggs,