Then Jeroboam built Shechem in mount Ephraim, and dwelt therein; and went out from thence, and built Penuel.
Jeroboam built Shechem - destroyed by Abimelech (Judges 9:1-49). It was rebuilt, and perhaps fortified by Jeroboam, as a royal residence.
Built Penuel - a ruined city with a tower (Judges 8:9), east of Jordan, on the north bank of the Jabbok. It was an object of importance to restore this fortress, as it lay on the caravan road from Gilead to Damascus and Palmyra, and secure his frontier on that quarter.