The Bible describes the location of garden of Eden.
Gen 2:8-14 The LORD God planted a garden eastward in Eden, and there He put the man whom He had formed. And out of the ground the LORD God made every tree grow that is pleasant to the sight and good for food. The tree of life was also in the midst of the garden, and the tree of the knowledge of good and evil. Now a river went out of Eden to water the garden, and from there it parted and became four riverheads. The name of the first is Pishon; it is the one which skirts the whole land of Havilah, where there is gold. And the gold of that land is good. Bdellium and the onyx stone are there. The name of the second river is Gihon; it is the one which goes around the whole land of Cush. The name of the third river is Hiddekel; it is the one which goes toward the east of Assyria. The fourth river is the Euphrates.
Let us identify the rivers mentioned in the map.
The first river skirts the whole land of Havilah.
1Sam 15:7 And Saul attacked the Amalekites, from Havilah all the way to Shur, which is east of Egypt.
Saul attacked Amalekites from Havilah all the way to Shur which is east of Egypt.
Gen 14:7 Then they turned back and came to En Mishpat (that is, Kadesh), and attacked all the country of the Amalekites, and also the Amorites who dwelt in Hazezon Tamar.
Num 13:26 Now they departed and came back to Moses and Aaron and all the congregation of the children of Israel in the Wilderness of Paran, at Kadesh; they brought back word to them and to all the congregation, and showed them the fruit of the land.
Based on the territorial description of the location of Amalekites, we can understand the location of Havilah is south of Israel.
The second river goes around the whole land of Cush. So, where is Cush?
Esth 1:1 NOW it came to pass in the days of Ahasuerus (this was the Ahasuerus who reigned over one hundred and twenty-seven provinces, from India to Cush),
|Kingdom of Kush (WIkipedia)|
The kingdom of Kush was known to ancient world since it existed from 1070 BC till AD 350 which matches the account in book of Esther. It is important to note the land of Cush does not refer to the territories of all the descendants of Cush before the tower of Babel because only this river is mentioned for Cush and not the other three, even though they flow through all the kingdom of Nimrod who is a descendant of Cush.
It is interesting to see the river goes around the land of Cush and it does indeed. Hence, Gihon is river Nile based on the Bible. It is also worth noting Gihon is also named for a pool within Israel during the time of kings (e.g., 1Kgs 1:33)
The fourth river is Eiddekel which flows east (or against as per LXX) of Assyria.
Gen 10:11 From that land he went to Assyria and built Nineveh, Rehoboth Ir, Calah,
We can see from the above map, all the cities in Assyria are along the river Tigris. Hence, Eddekel is the river Tigris.
The fourth river is Euphrates. This is the only river without further identification.
Mapping garden of Eden based on the rivers give the following result:
Hence, the entire region in the above map was the garden of Eden. It is important to note that the rivers in ancient world may not exist today. Hence, it may be futile to identify a main river that divides into four. However, based on the Havilah, land of Cush and the land of Assyria, the above map is arrived.