According to Biblical chronology, Abraham was born in 2166 BC, presumably in Ur of the Chaldeans in southern Iraq. He spent his early years in Ur until he migrated to Haran (Turkey) with the rest of his family (Gn 11:26-31). Scripture does not tell us when this migration took place, but it had to have been sometime prior to 2091 BC, the year Abraham left Haran at age 75 to answer God's call to go to Canaan (Gn 12:4). Abraham lived in Ur just prior to the historical period known as the Third Dynasty of Ur (Ur III), ca. 2100-2000 BC.
Bertrand Lafont, Scientific Director of Archaeology and Ancient History at the French Institute of the Near East, has pulled together the available ancient texts that bear on military activities of the Ur III period, providing fascinating insights into the culture that Abraham came out of. Go to http://cdli.ucla.edu/pubs/cdlj/2009/cdlj2009_005.html to read his article 'The Army of the Kings of Ur: The Textual Evidence.'
(For further background information on Abraham, see Stephen Caesar, 'The Wealth and Power of the Biblical Patriarchs,' Bible and Spade 19 , pp. 1-13.)