The Rhine flows from Lake Constance to the North Sea.
The river enters Lake Constance as the Alpine Rhine near Bregenz, Austria, and leaves it as the High Rhine near Stein am Rhein. It then runs west and north through Switzerland, Germany and the Netherlands before reaching the North Sea through a large delta. Lake Constance therefore forms a major link in the river’s upper course rather than a separate endorheic basin.
The Rhine has long been one of Europe’s most important transport routes. Cities including Basel, Strasbourg, Cologne and Rotterdam developed along its course, and the river connects Alpine headwaters with the world’s busiest port region. The Rhine also forms or has formed parts of several national borders.
A common mix-up is the Danube, which also rises in Central Europe but ultimately flows to the Black Sea. The Weser and Elbe reach the North Sea too, but neither passes through Lake Constance. Lake Constance itself consists chiefly of the Upper Lake, Lower Lake and the connecting Seerhein.