Hadith.2979 - Imam عليه السلام said:
"The boundary of Arafat includes the Valley of 'Uranah, Thuwiyyah, Namirah, and Dhi al-Majaz, and extends behind the mountain to its rear."
Arafat is not part of the Sacred Precinct (Haram), and the Haram is superior to it.
The boundary of Al-Mash'ar al-Haram extends from Al-Mazameen to the reservoirs (Hayad) and to the Valley of Muhassir.