The forest of Ephraim
Archimandrite Nikifor’s Biblical Encyclopedia
(2 Sam. 18:6) — a locality originally assigned to the sons of Joseph, being a wooded country (Josh. 17:10, 16), and, it seems, the part of it that remained uncleared was called the forest of Ephraim (1 Sam. 14:25, 26; 2 Kings 1:24 [as given]). Another such locality lay west of the Jordan, near Jabesh-gilead, and is historically notable for the battle between David and Absalom (2 Sam. 18:6), which ended in the destruction of Absalom.