Charles Ellicott Commentary 2 Samuel 20:21

"The matter is not so: but a man of the hill-country of Ephraim, Sheba the son of Bichri by name, hath lifted up his hand against the king, even against David; deliver him only, and I will depart from the city. And the woman said unto Joab, Behold, his head shall be thrown to thee over the wall." — 2 Samuel 20:21 (ASV)

Mount Ephraim. —The range of hills so called because much of it lay in the tribe of Ephraim, although extending south into Benjamin.