One of the things that has long been debated is the location of Noah's flood. The most popular, and most common claim, is that the flood was in Mesopotamia, or present day Iraq. But, as has been pointed out on this forum before by Alan F and others, the major problem with this theory is that the entire area drains into the Persian Gulf. There is no possible way Mesopotamia could have contained the flood waters. So a flood of the magnitude and duration described in Genesis could never have occurred there. The rain waters would simply run away into the ocean. The only way to make this work is to have God perform a miraculous event at the southern end, making an invisible wall, or barrier, to keep the flood waters within the region. But there is no indication in the biblical text that this occurred. So if Noah's flood did not take place in Mesopotamia, where else could it have taken place? The site of the flood would have to meet four requirements. First, it would have to be capable of containing the waters of the flood. In order to do this, we need a basin, with no outlet to the sea. If there were an outlet, the water would simply run out of the area. Second, the flood would have to fit the parameters mentioned in the Bible. Noah believed that the world was flooded, and that all the mountains were covered with water. Therefore this would require that the basin for the flood be large enough for Noah not to see any mountains from the center of the basin where the ark was floating. Third, this flood location would have to include the areas populated by Adam and Eve's descendants. That would include the area around the Garden of Eden, and east of the Garden. For when God drove them out of the Garden, he placed a cherubim at the east of the Garden (Genesis 3:24). This would indicate that Adam and Eve went east out of the Garden. We also have another clue in Genesis 4:16. Cain was sent away, and he settled in the land of Nod, which was east of Eden. Therefore, if we know the location of the Garden, we know the location of the Flood, since it had to cover the lands east of the Garden.
Finally, the ark landed on the mountains of Ararat. Note that the Bible says mountains of Ararat, and not "on Mount Ararat." The Ararat range is several hundred miles long, so the ark could be anywhere along this range. Although the taller mountains in the range are to the east, mountains extend westward all the way to the Mediterranean.
I believe the Caspian Sea is the most likely location for Noah's flood based on all the evidence. Here's why.
(From Wikipedia) "The Caspian Sea is the largest enclosed body of water on Earth by area ... It is an endorheic body of water (has no outflows), The Caspian ecosystem is a closed basin, with its own sea level history that is independent of the eustatic level of the world's oceans. The level of the Caspian has fallen and risen, often rapidly, many times over the centuries. Some Russian historians claim that a medieval rising of the Caspian caused the coastal towns of Khazaria, such as Atil, to flood."
It is clear that Noah would see no land, not even tall mountains, if he were in the center of a flood expanded Caspian Sea. For even in today's Caspian Sea, if you were in the middle of the southern portion, you would be over 180 miles from the tallest mountain, and you would see no mountains.
In his book, Legend: The Genesis of Civilization, a rchaeologist David Rohl proposes, I think quite convincingly, that the Garden of Eden was located in north-west Iran, near the city of Tabriz. (However, Rohl does not suggest the Caspian Sea location for Noah's flood.) According to Rohl the Garden of Eden was located in a vast plain referred to in ancient Sumerian texts as Edin, east of the Sahand Mountain, near Tabriz. He cites several geological similarities with Biblical descriptions, and multiple linguistic parallels as evidence. Additionally, he points out that this location is bound by the "headwaters" of four rivers, which Rohl identifies as those of the Pishon, the Gihon, the Tigris, and the Euphrates. (Gen. 2:10-14)
The map below shows the Caspian sea, and the part in yellow shows the drainage basin. Since this is a closed basin, so theoretically the waters of Noah's flood could have filled up and stood for an indefinite period of time in the entire area in yellow. In the lower left portion of the drainage basin we find the city of Tabriz,which is Rohl's location for the Garden of Eden. If Rohl is right, and if Adam and Eve and their descendants settled in the lands "East of Eden," as Genesis tells us they did, they would have lived near the Caspian Sea.
The requirement for the ark to land on the mountains of Ararat is met, because the mountains on the west side of the southern portion of the Caspian are within what is considered the Ararat range. In fact, Mount Ararat itself is within the drainage basin. However, given the elevation on the west side of the Caspian, it would not be possible to float the ark all the way to Mount Ararat. However, it could easily land on the slopes of the mountains to the east of Mount Ararat
I see only one problem with this understanding. From what I have read, the Caspian basin has few "flood deposits." This can be explained in one of two ways, if indeed Noah's flood did take place near the Caspian Sea. The flood took place a long, long time ago, (longer than some understand Genesis to indicate) since to completely erode flood sediments takes many thousands of years. Or the winds that God sent over the earth causing the flood waters to recede (Gen. 8:1) swept away the sediments that floods, which are not accompanied by such winds, normally leave behind.
I believer the Caspian Sea location for Noah's Flood fits all the parameters. It is a "closed basin" capable of holding onto the flood waters for a long period of time and also an area large enough to prevent Noah from seeing any surrounding land masses. Based on recent archaeological research by David Rohl, the Garden of Eden is believed to have existed just to the west of the flooded area. And finally the ark would have come to rest on mountains that are part of the Ararat range.
Thanks to Greg Neyman for much of the above information.