The Benrather line marks the border between the Northern German (or Low German)dialects and the High and Middle German dialects. The Line runs from Benrath (part of Düsseldorf) to East Germany in the area of Berlin and Magdeburg.

In the course of the Second Germanic consonant shift (taking place in approximately 500AD),in which the Low German dialects did not participate, the West Germanic languages were seperated along this line. The group of languages south of the line developed into High German – while the other West Germanic languages (English, Dutch, Frisian, and Low German) developed separately.

The Benrather line is also known as the Maken-machen line – After the consonant shift, the word 'to do, to make' was 'maken' in the Low German dialects, but 'machen' in the High German ones.

In the last decade the Benrather line has 'wandered' around the area of East Germany to the north, so the predominant dialect in Saxony-Anhalt has become an East Middle German Thuringian-Upper Saxon dialect, heavily influenced by Standard German. Until the Second World War, in the North, by far the majority of areas spoke East Low Saxon dialects.