Arafa also known as Arafat, is one of the sacred places for Muslims which is located in the Holy city of Makkah. On the 9th of Zilhajj, Muslim Pilgrims stay here to perform the obligatory ritual of Hajj. Arafah is called Arafah because Prophet Ibrahim  asked Angel Gabriel
 asked Angel Gabriel  , "Have you recognized me?" Gabriel
, "Have you recognized me?" Gabriel  replied, "Yes, I have recognized you!" This conversation took place on the plain of Arafah. That is why it is named Arafah.
 replied, "Yes, I have recognized you!" This conversation took place on the plain of Arafah. That is why it is named Arafah.
Read the full article here:Mastering the Method of Hajj: A Practical Approach