Wissen is a town in the district of Altenkirchen, in Rhineland-Palatinate, Germany. It is situated on the river Sieg, approximately 12 km northeā¦Wissen is a town in the district of Altenkirchen, in Rhineland-Palatinate, Germany. It is situated on the river Sieg, approximately 12 km northeast of Altenkirchen. Wissen is the seat of the Verbandsgemeinde Wissen.