Eden or more properly (the garden located in Eden) was Yahweh’s habitation on the earth.  It was not man’s garden, although Adam was a permanent guest in the garden.  But keep in mind that the garden was God’s dwelling or tabernacle on earth.  And where God dwells his family also dwells.  

If you consider the ancient near east you will likely conjure up images of vast deserts, arid climates, limited water and above average temperatures.  And I suspect that is not far off the mark.  Life was difficult;  it was a struggle to find food, water and other necessities to sustain life.  While much of the area was like this it also had areas that were well watered from the two great rivers the Tigris and Euphrates which flowed south emptying into the Persian Gulf.

If one were to consider the beliefs of polytheistic religions contemporaneous to the authorship of Genesis there was a belief that the gods would not have had a difficult life.  Rather they inhabited a place where there was no lack of provision.  Food, water and every provision necessary would have been plentiful.  The climate would have been desirable and life for the gods would be without distress.  Such places would include a garden as well as a mountain.

The author(s) of the Genesis account shared this understanding as Eden is pictured as a lush garden where life was pleasant, fellowship was sweet and suffering was non-existent.  Eden also provided the headwaters of four rivers and within the boundaries of Eden was a mountain.  In the past I used to think of the garden as something we might find at a wealthy persons estate, perhaps a few acres in size.  But recently I believe that I grossly underestimated the gardens vast diversity.  For instance consider these three points:

• The Lord God made all sorts of trees grow up from the ground—trees that were beautiful and that produced delicious fruit.
  Genesis 2:9

If we consider the vast differences of trees in the earth – they have unique demands for soil, water, temperature, amounts of sunlight, etc.  It seems unlikely these diverse requirements could be accommodated with a few acres.

• Second, a river flowed from the land of Eden, watering the garden and then dividing into four branches. Gen. 2:10

The four branches (Pishon, Gihon, Tigris, Euphrates) which had their source in the garden are not insignificant rivers.  So there must have been a vast supply of fresh water within the garden realm flowing outward.

• Lastly, the garden of Eden was the geographical region hosting the mountain of God.  From Ezekiel 28 consider these words:

You were in Eden, the garden of God……
I ordained and anointed you as the mighty angelic guardian.
You had access to the holy mountain of God
    and walked among the stones of fire.
Ezekiel 28:13-14

If you have a working knowledge of the Old Testament you will likely recall other passages where God is pictured as dwelling on a mountain or speaking from a mountain.  I specifically referenced the Ezekiel passage above since it clearly links Eden to the mountain of God.

I hope you can see that the garden of God was vast and expansive, filled with trees of every kind and conditions to support that vegetation, a mountain(1) which was the Lord’s abode and vast amounts of water likely flowing from this mountain to water the earth.

And Lot lifted his eyes and saw that the Jordan Valley was well watered everywhere like the garden of the Lord, like the land of Egypt, in the direction of Zoar.
Genesis 13:10

The other thing to note about the garden of Eden is that it was not the earth and the earth was not the garden.  This may seem self evident but let us consider the implications.  Adam was created before God planted the garden in Eden.  In other words he was in the world and Yahweh moved him into the garden after he planted it.  Further, Adam was told to fill the earth and subdue it.  He was not to fill and subdue Eden (that was already under God’s domain).  Rather, he was to go forth and make the rest of the earth resemble Eden.  Let me say it another way, Eden was the model or template and Adams job (as Yahweh’s representative) was to replicate Eden across the earth.

And God blessed them. And God said to them, “Be fruitful and multiply and fill the earth and subdue it, and have dominion over the fish of the sea and over the birds of the heavens and over every living thing that moves on the earth.”
Genesis 1:28

…then the Lord God formed the man of dust from the ground and breathed into his nostrils the breath of life, and the man became a living creature. ⁸ And the Lord God planted a garden in Eden, in the east, and there he put the man whom he had formed.
Genesis 2:7-8

Up to this point we have shown that God had a family before creating the earth.  His dwelling on earth was a desirable place where he lived with his human and divine family.  Adam’s responsibility was to multiply and bring the reality of Eden to the rest of the earth.