Where is the Garden of Eden ? Hidden here on Earth.

It is written (Psalm 104:2), "He wraps Himself in Light as a garment, [he spreads out the heavens like a curtain]."

עֹטֶה אוֹר כַּשַּׂלְמָה נוֹטֶה שָׁמַיִם כַּיְרִיעָה:

Rabbi Amorai asked: Where is the Garden of Eden ? He replied : It is on EARTH. - The Bahir (p. 12)

The Bahir: Illumination by Aryeh Kaplan http://amzn.to/2yoQfnz

His students said to him, "When will the kingdom come?"

Reb Y'Shua said, "It will not come by waiting for it. It will not be a matter
of saying 'here it is' or 'there it is.' Rather, the kingdom of the father is spread out upon the EARTH, and men do not see it." - (113) T'oma (The Twin)