It is a right tributary of the Rhine and 220.3 km (136.9 mi) in length with an elevation difference of 125 metres and a catchment area of 4.890 km².

Today's identified Roman camps are: Olfen, Xanten, Haltern, Oberaden, Holsterhausen, Anreppen and Beckinghausen.

Today, the river appears as a two-tier water course: Upstream, eastward of the city of Hamm, the catchment is more rural.

The historical city of Hamm and the towns Lünen, Haltern and Dorsten were small settlements located at the Lippe but expanded with the establishment of hard coal mines starting around 1900.

Until the 1970s water pollution played no important role in the public debate but the environmental policy changed over the decades.