How long is the Danube river?

The Danube is the second-longest river in Europe (after the Volga in Russia), and runs for a total length of 2,850km (1,770 miles) from its source near Donaueschingen, a town in the state of Baden-Württemberg in Germany, located within the Black Forest, and the Danube Delta, where the river empties into the Black Sea. The delta, the second largest such feature in Europe (after the Volga Delta) is primarily situated in Tulcea County in Romania, although its northern part is located within Ukraine's Odessa Oblast. Throughout its course, the Danube runs through a number of major cities in ten different countries, including four national capitals (Vienna, Bratislava, Budapest and Belgrade), the most of any river in the world.

https://www.britannica.com/place/Danube-River
https://en.wikipedia.org/wiki/Danube