Like many religious symbols, the Garden of Eden represents just that, a symbol. The fact which is much more important to Christians and other followers of God is that places such as the Garden of Eden are able to surpass physical time in regards to people's belief that it did exist. The actual reality of where it existed is not as important.
That being said, many have tried to find and denote the actual location. The following links have their own opinions on where the Garden actually lies.