The Longest Rivers in Bulgaria

A view of the Danube River in Bulgaria.
A view of the Danube River in Bulgaria.

Bulgaria is a country in Southeast Europe that encompasses a total area of 110,993.6 km2 and has an estimated population of 7,050,034. The country's landscape is rich in water resources, as it contains more than 300 rivers. Most rivers in the northern region of Bulgaria are tributaries of the Danube River, while those in the eastern region are short and drain into the Black Sea. Rivers in southern Bulgaria flow into the Aegean Sea, except for the Iskar, which flows into the Danube. The longest rivers in Bulgaria are highlighted below.

The 5 Longest Rivers in Bulgaria


The Danube River runs through Central and Eastern Europe and flows for 2,850 km across ten European countries before draining into the Black Sea. The river begins in Germany and flows eastwards to Ukraine. The Danube is the second longest river in Europe, after the Volga, and approximately 2,415 km of the river's course is navigable. Although the Danube has approximately 300 tributaries, its primary tributaries are the Drava, Sava, Morava, Inn, and Prut. The Danube's river basin extends over 42.5% of Bulgaria and gives rise to the Erma, Ogosta, Iskar, Osam, and Vit rivers that flow to the Danube.


The Maritsa River flows for 480 km from the Rila Mountains in Bulgaria to the Aegean Sea. Approximately 309 km of the river's course is located within Bulgaria. The Maritsa is also the longest river located completely within the interior of the Balkans. The river's drainage basin covers an area of about 53,000 km2, and 66.2% of this total falls within Bulgaria. The Marista forms part of the border between Bulgaria and Greece.


The Struma River flows for 415 km from the Vitosha Mountains in Bulgaria to the Aegean Sea in Greece. The river has a drainage basin that encompasses 17,330 km2, which includes 10,797 km2 in Bulgaria, while the remainder of the basin falls within Greece and North Macedonia. The Struma is the primary inflow and outflow of Lake Kerkini. Approximately 290 km of the river's course is located within Bulgaria.


The Tundzha River flows for 365 km from the Balkan mountain range in Bulgaria until it meets the Maritsa in Edirne, Turkey. 328 km of the river is located within Bulgaria, while the small remainder falls within the borders of Turkey. The Tundzha is fed 50 tributaries, but its primary tributaries are the Popovska, Sinapovska, and Mochuritsa.


The Iskar River flows for 368 km from the Rila Mountain Range to its confluence with the Danube. It is the longest river located entirely within Bulgaria, and is the primary source of the Iskar Reservoir. The Iskar has a significant economic role, as it provides water for domestic and industrial use.

Threats to Rivers in Bulgaria

The rivers in Bulgaria face similar problems as most rivers throughout the world. These include the clearing of water catchment areas to make room for agricultural land and altering the natural course of rivers to make them more navigable, which negatively impacts water quality. Additionally, the construction of dams to provide water for growing urban settlements impedes the migration of marine species, as well as the flow of nutrients and sediments.

List of the Longest Rivers in Bulgaria

RankRiverLength (km)

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