Southeast Europe or Southeastern Europe (SEE) is a geographical region of Europe, consisting primarily of the Balkans. Sovereign states and territories that are included in the region are, in alphabetical order: Albania, Bosnia and Herzegovina, Bulgaria, Croatia (alternatively placed in Central Europe), Greece, Kosovo,[a] Montenegro, North Macedonia, Romania, Serbia, and Turkey. Sometimes, Moldova and Ukraine (alternatively placed in Eastern Europe) and Slovenia (alternatively placed in Central Europe) are also included. The largest city of the region is Istanbul, followed by Bucharest, Sofia, Belgrade, and Athens.
There are overlapping and conflicting definitions of the region, due to political, economic, historical, cultural, and geographical considerations.
The first known use of the term "Southeast Europe" was by Austrian researcher Johann Georg von Hahn (1811–1869) as a broader term than the traditional Balkans, a concept based on the boundaries of the Balkan Peninsula (the countries that have been described as being entirely within the Balkan region are: Albania, Kosovo,[a] Bosnia and Herzegovina, Bulgaria, Montenegro, and North Macedonia).
Countries that are geographically, at least partially, described to be within the region are as follows:
In the CIA World Factbook, the description of each country includes information about "Location" under the heading "Geography", where the country is classified into a region. The following countries are included in their classification "Southeast Europe":