Jamieson, Fausset and Brown on Genesis 35:6

6. So Jacob came to Luz ... that is, Beth-el--It is probable that this place was unoccupied ground when Jacob first went to it; and that after that period [Calvin], the Canaanites built a town, to which they gave the name of Luz [Ge 28:19], from the profusion of almond trees that grew around. The name of Beth-el, which would, of course, be confined to Jacob and his family, did not supersede the original one, till long after. It is now identified with the modern Beitin and lies on the western slope of the mountain on which Abraham built his altar (Ge 12:8).