Ruhrkämpferehrenmal, Memorial monument in Horst district, Germany

The Ruhrkämpferehrenmal consists of 24 rectangular pillars made of Ruhr sandstone arranged in a circle, each rising to 3 meters high. The entire arrangement spans about 20 meters across and creates a striking stone composition within the Ruhr Valley landscape.

The memorial was built from April to November 1934 on the initiative of retired Lieutenant General Oskar von Watter, to designs by Essen architect Paul Dietzsch, on land provided by industrialist Wilhelm Vogelsang. It commemorated Freikorps, Einwohnerwehr, Reichswehr and police members killed in 1918–1920 fighting revolutionary workers, including the March 1920 general strike and the suppression of the Ruhr uprising. In 1985 the district council rededicated it as a Mahnmal; a memorial plaque approved in 1988 was installed in 1989 and later stolen.

The name refers to the Freikorps and Reichswehr members killed in the Ruhr fighting of 1918–1920, whom the Nazi builders cast as forerunners of their movement. Since 1985 the site has served as a Mahnmal, a warning memorial recalling the disputes over Germany's first republic. A plaque approved by the city council in 1988 was installed the following year, destroyed by vandals in 2011, and a replacement put up by the Steeler Archiv in 2015 was stolen in 2016.

The memorial stands on a purpose-built plateau about 25 metres above the north bank of the Ruhr, roughly 100 metres south-east of Haus Horst; the site is freely accessible at all times. The Bochum-Dahlhausen city border and the railway museum lie just east of the grounds. A panel donated in 2022 at the access road describes the memorial alongside Vryburg, Haus Horst and Villa Vogelsang.

The circular arrangement of pillars surprisingly resembles the prehistoric structure of Stonehenge, representing a rare modern example of this ancient architectural form. Bronze name plaques were later moved to the Essen City Archives for preservation and protection.