The Bible says regarding the location of Eden:
And a river went out of Eden to water the garden; and from thence it was parted, and became into four heads. (Genesis 2:10, KJV)
Two of these rivers are called Hiddekel (Tigris) and Perath (Euphrates).
This is why many Christians have assumed that the original garden was located somewhere in the Mesopotamian region (around present day Iraq) where the modern Tigris and Euphrates rivers flow.
However, the Bible records a devastating worldwide Flood, many centuries after Adam and Eve were expelled from the Garden. Sedimentary layers sometimes miles thick, bear mute testimony to this massive watery upheaval which tore apart and buried forever the pre-Flood world.
After the Flood, the survivors (Noah’s family) moved to the plain of Shinar (Sumeria/Babylonia) which is where we find rivers today called Tigris and Euphrates. These are therefore clearly not the same rivers. They run on top of Flood-deposited layers of rock containing billions of dead things (killed by the Flood). These rivers were probably named after the original pre-Flood rivers, just as settlers from the British Isles to America and Australia applied familiar names to many places in their ‘new world.’
Note also, that the Bible speaks of one river breaking into four, only two of which were called Tigris and Euphrates. This is not what is found in the Middle East today.
The Garden was destroyed by the Flood. Its actual location on the globe can never be established—for all we know it was where we now find the middle of the Pacific Ocean!