Many biblical scholars believe that the Garden of Eden, the original home of Adam and Eve, was located in Sumer, at the confluence of the Euphrates and Tigris (or Hiddekel) rivers in present-day Iraq. They presume that the geographical references in Genesis relate to the situation from the ninth to the fifth centuries BC and that the Pison and Gihon were tributaries of the Euphrates and Tigris which have since disappeared. In fact, they may have been ancient canals.

Other students of the Bible reason that if the four major rivers flowed out of the garden, then the garden itself must have been located far north of the Tigris-Euphrates civilization. They place the site in the mysterious northland of Armenia in present-day Turkey. This theory presumes that Gihon and Pison may not have been precise geographical designations, but rather vague descriptions of faraway places.

British archeologist David Rohl claimed that Eden is a lush valley in Iran, located about 10 miles from the modern city of Tabriz. Rohl suggests that the Gishon and Pishon are the Iranian rivers Araxes and Uizhun. He also identifies nearby Mt. Sahand, a snow-capped extinct volcano, as the prophet Ezekiel's Mountain of God.

There are those who say that the garden of God must have been in the Holy Land and that the original river that flowed into the garden before it split into four separate rivers must have been the Jordan, which was longer in the days of Genesis. The Gihon would be the Nile, and Havilah would be the Arabian Peninsula. Some supporters of this theory go further, stating that Mt Moriah in Jerusalem was the heart of the Garden of Eden and that the entire garden included all of Jerusalem, Bethlehem and Mt Olivet.

Supporters of Egypt as the site of the Garden of Eden claim that only the Nile region meets the Genesis description of a land watered, not by rain, but by a mist rising from the ground, in that the Nile ran partially underground before surfacing in spring holes below the first cataract. The four world rivers, including the Tigris and Euphrates, are explained away as beginning far, far beyond the actual site of Paradise.

Since Adam and Eve were the first humans, and since the oldest human remains have been found in East Africa, many people conclude that the Garden of Eden must have been in Africa. Likewise, when archaeologists discovered the remains of Pithecanthropus in Java in 1891, they guessed that Java was the location of the Garden of Eden.

Tse Tsan Tai, in his work The Creation, the Real Situation of Eden, and the Origin of the Chinese (1914), presents a case for the garden being in Chinese Turkestan in the plateau of eastern Asia. He claims that the river that flowed through the garden was the Tarim, which has four tributaries flowing eastwards.

In the mid-nineteenth century a theory developed that a vast continent once occupied much of what is now the Indian Ocean. The name Lemuria was created by British zoologist P.L. Sclater in honour of the lemur family of animals, which has a somewhat unusual range of distribution in Africa, southern India and Malaysia. Other scientists suggested that Lemuria was the cradle of the human race; thus it must have been the site of the Garden of Eden.

General Charles `Chinese' Gordon supported the theory that Africa and India used to be part of one massive continent. While on a survey expedition for the British government in the Indian Ocean, he came upon Praslin Island in the Seychelles group. So enchanted was he by this island, and by its Vallée de Mai in particular, that he became convinced that this was the location of the original Garden of Eden. The clincher for Gordon was the existence on Praslin of the coco-de-mer, a rare and exotic tree, which is native to only one other island of the Seychelles and which Gordon concluded was the tree of the knowledge of good and evil.

In his book The Sky People, Brinsley LePoer Trench argues that not only Adam and Eve but Noah lived on Mars. He states that the biblical description of a river watering the garden and then parting into four heads is inconsistent with nature. Only canals can be made to flow that way, and Mars, supposedly, had canals. So the Garden of Eden was created on Mars as an experiment by Space People. Eventually the north polar ice cap on Mars melted, and the descendants of Adam and Eve were forced to take refuge on Earth.

In 1886 the Rev. D.O. Van Slyke published a small pamphlet that expounded his belief that Eden was the area stretching from the Allegheny Mountains to the Rocky Mountains and that the Garden of Eden was located on the east bank of the Mississippi River between La Crosse, Wisconsin, and Winona, Minnesota. When the Deluge began, Noah was living in present-day Wisconsin, and the flood carried his ark eastward until it landed on Mt. Ararat.