In Genesis, geography links stories that are distant from each other in the text and can aid in understanding characters’ difficulties, motives, state of mind, and relationships with God and other people. Even topographical details like deserts, mountains, and rivers make significant contributions to the Genesis narratives.
In his book Genesis Unbound, John Sailhamer proposes an unusual but surprisingly compelling view of the four rivers in Genesis 2 – they define the territory in which the events of Genesis take place, perhaps even the approximate boundaries of a future Israel.
Genesis names the Tigris and Euphrates. Sailhamer proposes that the river that flows through Cush is the Nile (whose headwaters are in the ancient land of Cush, modern Ethiopia and Sudan) and points out that the only other major river in view in the Torah (the first five books of the Bible) is the Jordan.
With the exception of Noah’s post-flood experience, all the action in named places in the Torah happens in territory bounded by these rivers.
Following the flood, the ark lands on “one of the mountains of Ararat,” presumably in the modern region of the same name. Noah's descendants build cities along the Tigris and Euphrates.
Genesis 10 defines Canaan as parts of modern day Lebanon and Israel, preparing us for God's call of Abram in the coming chapters.