Albert Barnes Commentary 2 Samuel 2:9

"and he made him king over Gilead, and over the Ashurites, and over Jezreel, and over Ephraim, and over Benjamin, and over all Israel." — 2 Samuel 2:9 (ASV)

The Ashurites - If this term refers to the tribe of Asher, then the verse indicates the order in which Abner recovered the different districts from the Philistines and added them to the dominion of Ish-bosheth. He began with Gilead. Then, west of the Jordan, he gradually added the territory of Asher as far as Carmel, the entire plain of Esdraelon, and the country of Ephraim and Benjamin. This constituted, in effect, all of Israel, as distinguished from Judah.

This reconquest may have occupied five years, and Ish-bosheth’s reign over Israel may not have been reckoned to begin until the conquest was complete.