And the altars that were on the top of the upper chamber of Ahaz, which the kings of Judah had made, and the altars which Manasseh had made in the two courts of the house of the Lord, did the king beat down, and brake them down from thence, and cast the dust of them into the brook Kidron. (2 Kings 23:12)
This probably refers to an upper chamber constructed by Ahaz over some structure in the Temple court, since the writer is here dealing with Temple defilement. The altars may have been for star worship, which was expecially carried on from housetops (see Jer. 19:13; 32:29; Zeph. 1:5).