Kostiantynivka is an industrial city in Donetsk Oblast, eastern Ukraine. It is situated on the Kryvyi Torets river. In the Soviet era it developed into a major centre for the production of iron, zinc, steel, and glass. Administratively, it is incorporated as a city of oblast significance. It was the administrative center of the Kostiantynivka Raion until 2020, although it did not belong to it. After the raion was abolished, it was incorporated into the Kramatorsk Raion. Its population is approximately 67,350.