Part of Babylonia, on the Persian Gulf, which eventually assumed control of the whole country, so that Chaldea and Babylon were interchangeable. The rulers of Babylonia best known through the OT were Merodachbaladan and Nebuchadnezzar, the Chaldean kings (2 Kgs. 20: 12; 24: 1). The country had a reputation for its astrologers (Dan. 2: 2).