An unorthodox belief in God.

[Confused Ape]

I disagree, we have the mans tomb. Myths don't have real burial grounds;

http://en.wikipedia.org/wiki/Cave_of_the_Patriarchs

Situated beneath a Saladin-era mosque converted from a large rectangular Herodian-era structure, the series of subterranean chambers is located in the heart of the old city of Hebron (Al-Khalil) in the Hebron Hills. According to tradition that has been associated with both the Book of Genesis and the Quran, the cave and adjoining field were purchased by Abraham as a burial plot.

Hebron is in the right area.

Hebron (Arabic: About this sound الخليل (help·info) al-Khalīl; Hebrew:About this sound חֶבְרוֹן (help·info), Standard Hebrew: Ḥevron, Tiberian: Ḥeḇrôn ISO 259-3: Ḥebron; Ottoman Turkish Halilürrahman, Ancient Greek Hebrṓn, Χεβρών) is a Palestinian[3][4][5][6] city located in the southern West Bank, 30 km (19 mi) south of Jerusalem.

Unfortunately, tradition and myths don't prove that Abraham actually existed and the number of occupants in this cave increased as the tradition really got going.

According to Genesis, three biblical couples are buried there:

Abraham and Sarah (Genesis 23:1-20; Genesis 49:31)
Isaac and Rebekah (Genesis 35:29; Genesis 49:31)
Jacob and Leah (Genesis 49:28-33; Genesis 50:4-5; Genesis 50:12-13)

There is a Jewish tradition, that besides the three biblical couples mentioned above, that Adam and Eve were buried there also. (Zohar, Ruth 96) Certain Kabbalah texts also add that Moses and Zipporah are buried in the cave. [2]

Another Jewish tradition tells that when Jacob was brought to be buried in the cave, Esau prevented the burial claiming he had the right to be buried in the cave; after some negotiation Naphtali was sent to Egypt to retrieve the document stating Esau sold his part in the cave to Jacob. As this was going on Hushim, the son of Dan who was hard of hearing, did not understand what was going on, and why his grandfather was not being buried, so he asked for an explanation; after being given one he became angry and said: "Is my grandfather to lie there in contempt until Naphtali returns from the land of Egypt?" He then took a club and killed Esau, and Esau's head rolled into the cave.[37] This means that the head of Esau is also buried in the cave.

There's another interesting tradition about the cave.

According to the Midrash, the Patriarchs were buried in the cave because the cave is the threshold to the Garden of Eden. The Patriarchs are said not to be dead but "sleeping". They rise to beg mercy for their children throughout the generations. According to the Zohar,[41] this tomb is the gateway through which souls enter into Gan Eden, heaven.

The Jewish Virtual Library has more information. The Cave of Machpelah Tomb of the Patriarchs

The double cave, a mystery of thousands of years, was uncovered several years ago beneath the massive building, revealing artifacts from the Early Israelite Period (some 30 centuries ago). The structure was built during the Second Temple Period (about two thousand years ago) by Herod, King of Judea, providing a place for gatherings and Jewish prayers at the graves of the Patriarchs.

It's possible that a leader of a migration was buried here but it's unlikely that his name was Abram, later changed to Abraham. When the Mesopotamian creation and flood myths were adapted for a monotheistic religion the folk history of the migration would have been reworked to suit the religion as well.

Etymology of the name Abraham.

masc. proper name, name of the first of the patriarchs in the Old Testament, from Hebrew Abraham "father of a multitude," from abh "father" + *raham (cognate with Arabic ruham "multitude"); the name he altered from Abram "high father," from second element ram "high, exalted." Related: Abrahamic.

It's very convenient that this patriarch's original name happened to mean 'high father' in Hebrew because it was easily changed to a related name which meant 'father of a multitude' in Hebrew.