Karl married Karoline Leiningen-Dachsburg-Heidesheim on 16 Apr 1760 in Heidesheim, Pfalz, Bavaria. Karoline was born on 22 May 1734 in Heidesheim, Pfalz, Bavaria; died on 08 May 1810 in Frankfurt Am Main, Hessen-Nassau, Prussia. [Group Sheet] [Family Chart]

1. Prince of Nassau Karl Wilhelm was born on 26 Mar 1761 in Usingen, Hessen-Nassau, Prussia; died on 10 Mar 1763.
2. Princess of Nassau-Usingen Karoline Polyxene was born on 4 Apr 1762 in Schloss, Biebrich, Hessen-Nassau, Prussia; was christened on 5 Apr 1762 in Schloss, Biebrich, Hessen-Nassau, Prussia; died on 17 Aug 1823 in Rumpenheim, Starkenburg, Hesse-Darmstadt; was buried on 21 Aug 1823 in Rumpenheim, Starkenburg, Hesse-Darmstadt.
3. Princess of Nassau Luise Henriette Karoline was born on 14 Jun 1763 in Usingen, Hessen-Nassau, Prussia; died on 30 Mar 1845.
4. Prince of Nassau Son was born on 9 Mar 1768 in Usingen, Hessen-Nassau, Prussia.