The hill of Ammah lies before Giah on the way to the wilderness of Gibeon. (2 Samuel 2:24)
Abishai was at Gibeon under Joab his brother in the name of David to fight the servants of Ish-bosheth the son of Saul, led by Abner the son of Ner. Asahel, then Joab and Abishai pursued Abner until the sun started going down. The people of Benjamin gathered behind Abner to make a stand on the top of the hill of Ammah. Abner convinced Joab to cease battle. (2 Samuel 2)