Sayn-Wittgenstein-Hachenburg was a German County located in Rhineland-Palatinate, near the river Sieg.

Louise Isabelle Alexandrine Augusta, Countess of Sayn-Hachenburg, Burgravine of Kirchberg, full German name: Luise Isabelle Alexandrine Auguste, Gräfin zu Sayn-Hachenburg, Burggräfin von Kirchberg was the Princess consort of Nassau-Weilburg through her marriage to Frederick William, Prince of Nassau-Weilburg.