Kremenchuk (krĭmĭnchōkˈ) [key], Rus. Kremenchug, city (1989 pop. 237,000), central Ukraine, on the Dnieper River. It is the center of an industrial complex based on a hydroelectric plant; construction of the plant created the large Kremenchuk Reservoir nearby. Kremenchuk has a heavy machine industry and a small oil refinery. It was founded in 1571 as a fortress.