Albert Barnes Commentary 1 Kings 12:1

"And Rehoboam went to Shechem: for all Israel were come to Shechem to make him king." — 1 Kings 12:1 (ASV)

The first step taken by the new king was a most judicious one. If anything could have removed the disaffection of the Ephraimites and caused them to submit to the ascendency of Judah, it would have been the honor shown to their capital by selecting it as the location for the coronation.

Shechem (now Nablus) was situated on the slope of Mount Gerizim, directly opposite Mount Ebal, in a location second to none in all Palestine. Although Abimelech had destroyed the city (Judges 9:45), it had likely risen again quickly and was once more a chief city—perhaps the chief city—of Ephraim. Its central location made it a convenient place for the general assembly of the tribes, just as it had been in the days of Joshua (Joshua 8:30–35; Joshua 24:1–28), which provided an additional reason for its selection.