During the late 19th century, the first excavators of Nekhen, with them Quibell, were interested in the necropolis of the opposite bank of the Nile: the hill of Elkab.
It was mainly dated from the beginning of the 18th dynastide with the graves of Paheri and Ahmose son of Abana, who had already delivered their written testimonies.
Paheri was nomarch of Nekheb, "administrator of the land to grain for the Southern District, from Per-Hathor up to Nekheb." Ahmose son of Abana grew up in the city of Nekheb and testified the Hyksos battles.
We can conclude from these two autobiographies that Nekheb was the city near the necropolis, on the same side of the Nile. It represent one of the first Egyptian urban centers from the pre-dynastic and Old Kingdom.
Recent discoveries are still made there:
The city of Nekheb has dominated Nekhen as the capital of the third nome of Upper Egypt from the Old Kingdom. The Egyptian name of this city comes from the goddess Nekhbet, who had a temple at the end of the 4th millennium BC.
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My notes of veracity :
The city of Nekheb has its ruins at Elkab: 5/5