Geography of Bulgaria

Bulgaria is a country situated in Southeast Europe that occupies the eastern quarter of the Balkan peninsula, being the largest country within its geographic boundaries. It is bordering Romania to the north, Serbia and North Macedonia to the west, Greece and Turkey to the south, and the Black Sea to the east. The northern border with Romania follows the river Danube until the city of Silistra. The land area of Bulgaria is (), slightly larger than that of Cuba, Iceland or the U.S. state of Tennessee. Considering its relatively compact territorial size and shape, Bulgaria has a great variety of topographical features. Even within small parts of the country, the land may be divided into plains, plateaus, hills, mountains, basins, gorges, and deep river valleys. The geographic center of Bulgaria is located in Uzana.

Bulgaria features notable diversity with the landscape ranging from the snow-capped peaks in Rila, Pirin and the Balkan Mountains to the mild and sunny Black Sea coast and southernmost valleys; from the typically continental Danubian Plain (ancient Moesia) in the north to the strong Mediterranean climatic influence in the valleys of Macedonia and in the lowlands in the southernmost of Thrace, the lowest parts of the Upper Thracian Plain, along the Maritsa. Most of the country is situated within the humid continental climate region, with Alpine climate in the highest mountains and subtropical climate in the southernmost regions.

The country has a dense river network but with the notable exception of the river Danube, rivers are mostly short and with low water flow. The average annual precipitation is 670 mm; the rainfall is lower in the lowlands and higher in the mountains. The driest region is Dobrudzha in the north-eastern part of the Danubian Plain (450 mm), while the highest rainfall has been measured in the upper valley of the river Ogosta in the western Balkan Mountains (2293 mm).

Bulgaria has substantial land in agriculture and forest. In 2006 land use and land cover was 5% intensive human use, 52% agriculture including pasture, 31% forest, 11% woodland-shrub, grassland, and non-vegetated, and 1% water.

Phytogeographically, Bulgaria straddles the Illyrian and Euxinian provinces of the Circumboreal Region within the Boreal Kingdom. The country falls within six terrestrial ecoregions of the Palearctic realm: Balkan mixed forests (main), Rodope montane mixed forests (main in the mountains), Euxine-Colchic deciduous forests, Aegean and Western Turkey sclerophyllous and mixed forests, East European forest steppe and Pontic–Caspian steppe.

Boundaries and territory

The borders of Bulgaria have a total length of 2,245 km; of them 1,181 km are land boundary and 686 km are formed by rivers. The coastline is 378 km.

The northern border with Romania is 609 km. Most of the frontier (470 km) is formed by the river Danube from the mouth of the river Timok in the west to the city of Silistra in the east. The land border from Silistra to Cape Sivriburun at the Black Sea is 139 km long. The Danube, with steep bluffs on the Bulgarian side and a wide area of swamps and marshes on the Romanian side, is crossed by two bridges – New Europe Bridge between Vidin and Calafat, and Danube Bridge between Ruse and Giurgiu. There are 48 Bulgarian and 32 Romanian islands along the river Danube; the largest one, Belene (41 km²), belongs to Bulgaria. The land frontier has three border crossings at Silistra, Kardam and Durankulak at the Black Sea. It is also crossed by a major gas pipeline transporting natural gas from Russia to Bulgaria.

The eastern border (378 km) is maritime and encompasses the Bulgarian Black Sea Coast from Cape Sivriburun in the north to the mouth of the Rezovo River in the south. Bulgaria's littoral forms 1/10 of the total Black Sea coastline, and includes two important gulfs, the Gulf of Varna and the Gulf of Burgas, harbouring the country's two major ports.

The southern border is 752 km long, of them 259 km are with Turkey and 493 km are with Greece. The Bulgaria–Turkey frontier runs from the mouth of the Rezovo River in the east through the Strandzha Mountains and the Dervent Heights, crosses the river Tundzha at the village of Matochina and ends at the river Maritsa. There are three border crossings at Malko Tarnovo, Lesovo and Kapitan Andreevo. The border with Greece runs from Kapitan Andreevo through several ridges of the Rhodope Mountains, generally following the watershed of the rivers Arda and Vacha on the Bulgarian side, runs through the Slavyanka Mountain, crosses the river Struma at the village of Kulata and runs through the crest of the Belasitsa Mountain to the Tumba Peak. There are six border checkpoints at Svilengrad, Ivaylovgrad, Makaza, Zlatograd