The Wölpe has its source in a depression southeast of Erichshagen-Wölpe [de], a village in the borough of Nienburg and flows towards the northeast.

In front of Rethem the Weiße Graben ("White Ditch") links the Wölpe with the Alpe.

During the Middle Ages the waterway was widened into a moat for the security of the fortified position and flowed around the castle built in the 12th century.

After the destruction of the site in the 17th century the castle moat and the Wölpe were filled with rubble.

About 4 km (2.5 mi) further on near Heemsen the Wölpe flows into the wood by the site of the 9th century Brunsburg [de] castle.