Eastern Europe is a subregion of the European continent. As a largely ambiguous term, it has a wide range of geopolitical, geographical, ethnic, cultural, and socio-economic connotations. Its eastern boundary is marked by the Ural Mountains, whilst its western boundary is defined in various ways. Most definitions include the countries of Belarus, Russia, Ukraine, Moldova and Romania while less restrictive definitions may also include some or all of the Balkans, the Baltic states, the Caucasus and the Visegrád group.

The Balkans, corresponding partially with the Balkan Peninsula, is a geographical area in southeastern Europe with various geographical and historical definitions. The region takes its name from the Balkan Mountains that stretch throughout the whole of Bulgaria. The Balkan Peninsula is bordered by the Adriatic Sea in the northwest, the Ionian Sea in the southwest, the Aegean Sea in the south, the Turkish straits in the east, and the Black Sea in the northeast. The northern border of the peninsula is variously defined. The highest point of the Balkans is Musala, 2,925 metres (9,596 ft), in the Rila mountain range, Bulgaria.