Albert Barnes Commentary 2 Samuel 20:2

"So all the men of Israel went up from following David, and followed Sheba the son of Bichri; but the men of Judah clave unto their king, from the Jordan even to Jerusalem." — 2 Samuel 20:2 (ASV)

From Jordan... — The men of Israel only escorted David from the Jordan River to Gilgal and left him there; but the men of Judah, as a group, went with him all the way to Jerusalem.