The Söse rises on the plateau of Auf dem Acker in the district of Göttingen in the southwestern part of the Harz Mountains in Germany.

In Osterode the river bends northwest, only to swing westwards near Badenhausen and then southwards near Eisdorf just a few kilometres west of the Harz.

It flows in that direction through Osterode-Dorste before entering the westward-flowing Rhume between the villages of Berka [de] and Elvershausen [de], both part of the borough of Katlenburg-Lindau in the district of Northeim.

148[4] in the system of checkpoints in the Harzer Wandernadel hiking network.

The Morgenbrodt Hut was demolished in 2013 by the National Park Authority as it was falling down and it is not intended to be replaced.