So the Israelites and Absalom camped in the land of Gilead.

2 Samuel 17:25
Absalom had appointed Amasa over the army in place of Joab. Amasa was the son of a man named Ithra, the Ishmaelite who had married Abigail, the daughter of Nahash and sister of Zeruiah the mother of Joab.

2 Samuel 17:27
When David came to Mahanaim, he was met by Shobi son of Nahash from Rabbah of the Ammonites, Machir son of Ammiel from Lo-debar, and Barzillai the Gileadite from Rogelim.

2 Samuel 18:6
So David's army marched into the field to engage Israel in the battle, which took place in the forest of Ephraim.

So Israel and Absalom pitched in the land of Gilead.