Most Bible commentaries state that the site of the Garden of Eden was in the Middle East, situated somewhere near where the Tigris and Euphrates Rivers are today. This is based on the description given in Genesis 2:8–14:
The Lord God planted a garden eastward in Eden.... 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.... The name of the second river is Gihon.... The name of the third river is Hiddekel [Tigris].... The fourth river is the Euphrates.
Even the great theologian John Calvin struggled over the exact location of the Garden of Eden. In his commentary on Genesis he states:
Moses says that one river flowed to water the garden, which afterwards would divide itself into four heads. It is sufficiently agreed among all, that two of these heads are the Euphrates and the Tigris; for no one disputes that ... (Hiddekel) is the Tigris. But there is a great controversy respecting the other two. Many think, that Pison and Gihon are the Ganges and the Nile; the error, however, of these men is abundantly refuted by the distance of the positions of these rivers. Persons are not wanting who fly across even to the Danube; as if indeed the habitation of one man stretched itself from the most remote part of Asia to the extremity of Europe. But since many other celebrated rivers flow by the region of which we are speaking, there is greater probability in the opinion of those who believe that two of these rivers are pointed out, although their names are now obsolete. Be this as it may, the difficulty is not yet solved. For Moses divides the one river which flowed by the garden into four heads. Yet it appears, that the fountains of the Euphrates and the Tigris were far distant from each other.
Calvin recognized that the description given in Genesis 2 concerning the location of the Garden of Eden does not fit with what is observed regarding the present Tigris and Euphrates Rivers. God’s Word makes it clear that the Garden of Eden was located where there were four rivers coming from one head. No matter how one tries to fit this location in the Middle East today, it just can't be done.
Interestingly, Calvin goes on to say:
From this difficulty, some would free themselves by saying that the surface of the globe may have been changed by the deluge...
This is a major consideration that needs to be taken into account. The worldwide, catastrophic Flood of Noah's day would have destroyed the surface of the earth. If most of the sedimentary strata over the earth's surface (many thousands of feet thick in places) is the result of this global catastrophe as creationists believe, then we would have no idea where the Garden of Eden was originally located—the earth’s surface totally changed as a result of the Flood.