King James Bible Dictionary

Fortress of Chemosh, a city on the west bank of the Euphrates (Jeremiah 46:2; 2 Chronicles 35:20), not, as was once supposed, the Circesium at the confluence of the Chebar and the Euphrates, but a city considerably higher up the river, and commanding the ordinary passage of the Euphrates; probably identical with Hierapolis. It was the capital of the kingdom of the northern Hittites. The Babylonian army, under Nebuchadnezzar, the son of Nabopolassar, here met and conquered the army of Pharaoh-necho, king of Egypt (B.C. 607). It is mentioned in monuments in B.C. 1600 and down to B.C. 717.

A Babylonian city on the Euphrates, against which the king of Egypt made war.
2 Chronicles 35:20; Isaiah 10:9; Jeremiah 46:2

(fortress of Chemosh) occupied nearly the site of the later Mabug or Hierapolis. It seems to have commanded the ordinary passage of the Euphrates at Bir or Birekjik . Carchemish appears to have been taken by Pharoah Necho shortly after the battle of Megiddo (cir. B.C. 608), and retaken by Nebuchadnezzar after a battle three years later, B.C. 605. (Jeremiah 46:2)