He was buried in his tomb in the garden of Uzzah, and his son Josiah replaced him as king.
TSK
TSK · 2 Kings 21:18
Treasury of Scripture Knowledge references in NET.
Jehoram was thirty-two years old when he became king and he reigned eight years in Jerusalem. No one regretted his death; he was buried in the City of David, but not in the royal tombs.
When they withdrew, they left Joash badly wounded. His servants plotted against him because of what he had done to the son of Jehoiada the priest. They murdered him on his bed. Thus he died and was buried in the City of David, but not in the tombs of the kings.
Hezekiah passed away and was buried on the ascent of the tombs of the descendants of David. All the people of Judah and the residents of Jerusalem buried him with great honor. His son Manasseh replaced him as king.
He will be left unburied just like a dead donkey. His body will be dragged off and thrown outside the gates of Jerusalem.’”