Düsseldorf is the capital city of North-Rhine Westphalia, the most populous state of of Germany. It is the second-largest city in the state after Cologne and the sixth-largest city in Germany, with a 2022 population of 629,047.

The Düssel, from which the city and the borough of Düsseltal take their name, divides into four separates branches of within the city, each with its own mouth into the Rhine (Lower Rhine).