Southeast Europe
This concept is based on the boundaries of the Balkan peninsula. The countries that have been described as being entirely within the region are: Albania, Kosovo, Bosnia and Herzegovina, Bulgaria, Macedonia and Montenegro.
Bulgaria
The Balkan mountains run laterally through the middle of the country. The mountainous southwest has two distinct alpine ranges—Rila and Pirin, which border the lower but more extensive Rhodope Mountains to the east. Musala, at , is the highest point in both Bulgaria and the Balkan peninsula, and the Black Sea coast is the country's lowest point. Plains occupy about one third of the territory, while plateaux and hills occupy 41%. Most rivers are short and with low water levels. The longest river located solely in Bulgarian territory, the Iskar, has a length of . Other major rivers include the Struma and the Maritsa in the south.