He is married to Isabella Charlotte Amelia gravin van Nassau LaLecq.
They got married on July 2, 1782 at Utrecht, Utrecht, Netherlands, he was 23 years old.
Child(ren):
http://worldroots.com/brigitte/royal/fatherofeurope/geeroudegeindesc.htm
Jhr. Willem Carel Pieter de Geer <http://worldroots.com/brigitte/royal/bio/willemgeerbio1759.html>Heer van Oudegein en Rijnhuizen Born 20 March 1759 Utrecht Died 28 October 1831 Jutfaas, H.Oudegein Married 2 July 1782 Utrecht Countess Isabella Charlotte Emilie van Nassau-La Lecq, daughter of Count Jan Nicolaas Floris van Nassau-La Lecq and Maria Anna Testas Born 25 July 1755 Utrecht Died 7 February 1842 Utrecht Children, Generation I
Generation I 1 Jhr. Jan Jacob de Geer <http://worldroots.com/brigitte/royal/bio/jandegeerbio1784.html>Heer van 't Gein en Oudegein Born 3 April 1784 Utrecht Died 6 November 1871 Utrecht Married 11 December 1808 Utrecht Jkvr. Elisabeth Sophia Jacoba Falck, daughter of Jhr. Mr. Otto Willem Philippus Falck and Elisabeth Jacoba van Schuler Born 24 February 1780 Utrecht Died 17 February 1848 Utrecht Children, Generation II-1 2 Jhr. Jean Florent Anne de Geer van Oudegein Born 2 November 1786 Utrecht Died 27 March 1842 Utrecht Married 30 October 1819 Haarlem Jkvr. Regina Catharina Huyghens, daughter of Jhr. Hendrik Huyghens and Anna Adriana Balde Born 12 August 1792 Amsterdam Died 16 November 1820 Haarlem Children, Generation II-2 3 Jkvr. Theodora Anna Anthonia de Geer Born 15 May 1788 Utrecht Died 13 February 1879 Utrecht
The data shown has no sources.