One calf he set up in Bethel, and the other in Dan.
We have here the beginning of the reign of Jeroboam. He built Shechem first and then Penuel - beautified and fortified them, and probably had a palace in each of them for himself (Kg1 12:25), the former in Ephraim, the latter in Gad, on the other side Jordan.
Commenting on 1 Kings 12:25-33
And he made an house of high places,.... Or "altars" (s), built a temple at Dan, and set up several altars in it for sacrifice, both for burnt offerings, and for incense, as at Jerusalem: and made priests of the lowest of the people; this clause seems not so well rendered; for this would have been very unpopular, and brought his new form of worship...
One in Beth-el, and the other - in Dan - One at the southern and the other at the northern extremity of the land. Solomon's idolatry had prepared the people for Jeroboam's abominations!