The natural landscape of Bulgaria is diverse, consisting of lowlands, plains, foothills and plateaus, river valleys, basins, and mountains of varying elevations. About 70% of the country’s territory is hilly land and 30% is mountainous. The average elevation of the country’s territory is 467 m, generally decreasing from south to north and from west to east.
In the central part of the country lies the Balkan Mountain Range, where the highest peak is Botev (2,376 m). From south to north, its western area is crossed by the Iskar River, which forms a picturesque gorge more than 70 km long. The northern arm of the Balkan Mountains is mainly karst. The highest peak in this range is Vasilyov (1,490 m).
To the south of the Balkan Mountains are the western Balkan valleys and the Srednogorie (central mountainous region). The largest valley in the southern arm of the Balkans is the Sofia valley, the location of the Bulgarian capital Sofia. The mountains in the Srednogorie are the Zavalsko-Planska Range, the Ihtimansko Srednogorie, the Sashtinska Sredna Gora, and the Sarnena Gora.
Between the northern arm of the Balkans and the Danube River lies the Danube valley, with an area of roughly 31,000 square meters. Its eastern part consists of plateaus – the Dobrudzha plateau, the Plovadia plateau, the Lilyak plateau, and the Shumen plateau, among others. To the north lie the Trans-Danube lowlands, which occupy the terraces of the Danube river.
To the south of the capital Sofia rises the mountain Vitosha, whose highest peak is Cherni Vrah (2,290 m). Its foothills extend to the middle part of western Bulgaria, where low-lying and medium-elevation mountains alternate, such as Ruy, Milevska, Zemenska, Konyavska, Verila, and others. West of the Struma River valley and south of Kraishteto is the Osogovo-Belasishka mountain range, which includes the peaks of Osogovska (Mount Ruen, 2,251 m), Vlahinska, Maleshevska, Ograzhden and Belasitsa (Mount Radomir, 2,029 m).
Bulgaria has a wide variety of minerals. According to the national records detailing the reserves and resources of Bulgaria’s mineral deposits, 163 types of minerals have been found in the country, 7 types of which are fuel and energy resources, 14 types are ore, 75 types are non-ferrous, and 67 types are viable as rock covering and construction material.
The small territorial range of Bulgaria and its close proximity to the Danube River and the Black Sea, together with the location of the Balkan Mountains and its proximity to the Aegean Sea are preconditions for short river arteries and small river systems. The Iskar River is the longest river in Bulgaria (368 km), which empties into the Danube River and has its headwaters in the Rila Mountains. Other large rivers that empty into the Danube river are the Lom, the Ogosta, the Vit, the Osam, and the Yantra. The rivers directly flowing into the Black Sea collect their waters from the easternmost parts of the Danube valley, the northern arm of the Balkans, the Balkan Mountains and Strandzha. These are the Batovska, the Devnya, the Provadiyska, the Kamchia, the Dvoynitsa, the Fakiyska, the Izvorska, the the Ropotamo, the Dyavolska, the Karaagach, the Veleka and the Rezovska Rivers. The largest Bulgarian river within the Aegean drainage basin is the Maritsa (321 km long, with an area of 21,084 square km). Other large rivers are the Arda, the Tundzha, the Mesta, and the Struma.
Three national parks have been established in the country: Pirin National Park (a UNESCO natural heritage site), Rila National Park, and the Central Balkans National Park. There are also 11 nature reserves – Belasitsa, Balgarka, Vratsa Balkan, Golden Sands, Persina, Rila Monastery, Rusenski Lom, Sinite Kamani, Strandzha and the Shumen Plateau.