Eastern Ukraine (or East Ukraine) is an important geographical term and generally includes territories of Ukraine east of the Dnieper river, particularly Sloboda Ukraine, the Donets Basin ("Donbas"), and Azov Sea Littoral. Almost a third of the country's population lives within the region, which includes three cities with populations over a million. The major river of eastern Ukraine is Seversky Donets.
The territory is heavily urbanized and commonly associated with the Donbas. The three largest metropolitan cities form an industrial triangle within the region.