The so-called Hisham Palace, which was built in the late phase of the Umayyad rulership (661-750 CE), is located outside the historical city limits of Jericho in the West Jordan country*.
Main reference until today is Hamilton, Robert William, and Oleg Grabar, Khirbat al Mafjar, an Arabian Mansion in the Jordan Valley (Oxford: Clarendon Pr, 1959)
*Jericho is located in the so-called A zone, the fragmented area under Palestinian administration, which makes up 22% of the area, which had been given by the UN partition plan in 1947 to the Palestinians: i.e. 49% of what was originally Palestine (until 1946), while 51% was intended for the emerging state of Israel.