It forms the longitudinal axis of the former parish of Blasheim, on which the farms and mills of the Mehner Dorf are situated.

The eastern headstream rises not far from the summit of the Kahle Wart near the boundary with the parish of Hüllhorst, the western one in an area that is known as Gerliethe.

The Mehner Bach then flows generally north-northwest through the Lübbecke Loessland, through the two villages of Obermehnen and Untermehnen, then through Blasheim and Eikel and finally through the Hollwinkel Wood.

As it enters the aforementioned wooded area the stream leaves the territory of Lübbecke and flows for around 700 metres on the land of the borough of Preußisch Oldendorf, before emptying into the Große Aue not far from the village of Hedem.

Just southwest of the Hollwinkel Wood the stream forms the boundary between the boroughs ofLübbecke and Preußisch Oldendorf for around 50 metres.