The place name "Dilmun" appears in the texts of Ebla, such as a unit of weight for the wool trade. It is also attested in an inscription from Ur-Nanshe of Lagash during the same time, around the 24th century BC. It then appears in many texts related to trade long distances: Mari, Ur, Larsa and some archives of merchants from the early second millennium.
Its location as island in the Persian Gulf does not seem very realistic for many researchers. Because of the goods traded by the merchants of Dilmun : wool, wood, precious stones, copper, ... Also, some have suggested a place north of Basra in Mesopotamia.
Other researchers propose the site of Qal'at al-Bahrain as Capital of Dilmun. It is a mountain of 300 × 600 m on the island of Bahrain. Nine Danish excavations extending from 1955 to 1978, complemented by the work of the French archaeological mission in Bahrain led by Pierre Lombard, showed a continuous human occupation from 2300 BC until the 16th century after J .-C. On the 12 m height of the mound, a fort was built by the Portuguese during the last century of this period.
Some cuneiform tablets of the Kassite period were found there, including some mentions of a king « Agum ». However these do not confirm that Qal'at al-Bahrain was "Dilmun".
Recent archaeological excavations of graves showed that the island had a system of weights and measures identical to that of the Indus Valley. The seals found in the tombs of Harappa are resembling those of Bahrain and or those of the Kuwait Failaka. This latter island is an another candidate for "Dilmun". A confederation of islands appears to be a possibility for the country of Dilmun or Tilmun.
At Saar, another Bahrain site, excavations are successful and confirm a presence in all the island during the 3rd millennium BC: