Which river flows through the most countries?

The Danube flows through or borders the most countries of any river: ten in total. It begins in Germany’s Black Forest and travels southeast for about 2,850 kilometres before reaching the Black Sea through its delta.

From Germany, the Danube passes through or forms borders with Austria, Slovakia, Hungary, Croatia, Serbia, Romania, Bulgaria, Moldova and Ukraine. Because rivers frequently form international boundaries, “flows through” is often understood geographically to include countries whose borders the river marks. Under that standard quiz convention, the Danube is the accepted answer.

The river has been an important European route since antiquity and once marked part of the Roman Empire’s northern frontier. Today it links four national capitals—Vienna, Bratislava, Budapest and Belgrade—more than any other river. About 2,415 kilometres of the Danube are navigable.

A common mix-up is the Nile or Amazon, which are longer or drain larger regions but cross fewer sovereign countries. The Danube’s distinction is political geography rather than length.