Rheinmünster is a municipality located in the district of Rastatt within the state of Baden-Württemberg, Germany. The town was formed in 1974 through the amalgamation of four formerly independent councils: Greffern, Schwarzach, Soellingen, and Stollhofen.
The name of the municipality is derived from two primary geographical and historical features: the Rhine River, which neighbors the town, and the "Münster," referring to a Benedictine abbey. This abbey was eventually subject to secularisation in 1803.