Well that all depends upon which theory
of Atlantis you believe.
If you think Plato was
telling the truth in Timaeus and Critias
then Atlantis is located somewhere in the middle of the Atlantic Ocean.

One of the more likely places would be around the Azores Islands. The
Azores are a group of islands belonging to Portugal located about 900 miles
(1500 km) west of the Portugese coast. Some people believe the islands
are the mountain tops of the sunken continent of Atlantis.

(For more information about the Atlantic theory click
here.)
On the other hand, if you feel that Atlantis was
an exaggeration of the historical destruction of Thera and the Minoan empire,
then it is found in the Aegean.

The island of Thera, also known as Santorini, is a volcanic island located
due north of Crete in the Aegean Sea. Sometime around 1500 BC is was devasted
by a volcanic explosion that may have contributed to the sudden downfall
of the Minoan civilization.

(For more information about the Thera theory click
here.)
But, if you believe Atlantis was simply a story
then it was only located in the long decayed brain of Plato.
