Jamieson, Fausset and Brown on 2 Kings 23:13-14

13-14. the high places ... which Solomon ... had builded--(See on 1Ki 11:5).

the right hand of the mount of corruption--The Mount of Olives is a hilly range on the east of Jerusalem. This range has three summits, of which the central one is the Mount of Corruption, so called from the idol temples built there, and of course the hill on the right hand denotes the southernmost peak. Josiah is said not to have destroyed, but only defiled, "the high places on the hill of corruption." It is most probable that Hezekiah had long before demolished the idolatrous temples erected there by Solomon but, as the superstitious people continued to regard the spot as consecrated ground, Josiah defiled it.