As far as the gender of river names is concerned, the most important rule in German is that there is no rule – unlike, for example, in Latin, where the rivers are always masculine, where the Danube is also called “Danuvius”. In German, gender depends on several things.
Pay attention to the ending
First, whether there might be another word in the river name. For example, many rivers in southern Germany end in “ach” such as the Schwarzach, the Wutach or the Salzach. They are female because the Ach is an old German expression for river. So the Schwarzach is nothing other than the black river. The Danube is similar: it has the same root as the Russian river Don, namely the Indo-European word “Duna”, “river”. And so the Danube floodplain is the floodplain of the river. And because the Aue is female, so is the Donau.
Celts, Romans, Germans – all left their mark
This also shows that the names of our rivers come from very different epochs. Celts, Romans, Germans – they were all here. And depending on who gave a river its name, its traces have survived. The Germans mostly gave the rivers female names, the Romans more male ones, because at least the big rivers were often associated with gods.
Panta rhei – everything flows
In the case of the Rhine, it is not entirely clear whether the name, and thus also the male gender, was introduced by the Romans – as Rhenus – or by the Celts before that. It is interesting here that the Rhine probably has the same word root as the French Rhone, namely “rhei” – to flow. The classical philologists among us still know the sentence of Heraclitus: Panta rhei – everything flows. This is apparently the same “rhei” as in the Rhine. It’s also in the German word “rinn”, although the Rhine is of course anything but a trickle.
These few examples show that most of our rivers are female, some male. But there is no clear rule and much depends on the historical circumstances of the naming. And sometimes it also jumps: The Rhone is called “le Rhône” in French – so it’s male.
Thanks to Prof. Konrad Kunze