Claas married Harmke Pieters on 18 April 1795 in Bedum, Groningen, Nederland. Harmke (daughter of Pieter Pieters and Annegien Claessen) was born approximately 1776 in Bedum, Groningen, Nederland; died on 21 July 1844 in Groningen, Groningen, Nederland. [Group Sheet] [Family Chart]

1. Annigje Claassens Mensinga was born in 1798 in Zuidwolde, Bedum, Groningen, Nederland; was christened on 22 April 1798 in Zuidwolde, Bedum, Groningen, Nederland; died on 23 November 1839 in Helpman, Haren, Groningen, Nederland.
2. Gerrit Klaasen Mensinga was born in 1801 in Groningen, Groningen, Nederland; was christened on 05 July 1801 in Groningen, Groningen, Nederland; died on 14 July 1872 in Zuidwolde, Bedum, Groningen, Nederland.
3. Trijntje Mensinga was born in 1806 in Groningen, Groningen, Nederland; was christened on 10 January 1806 in Groningen, Groningen, Nederland; died in Date unknown.
4. Pieter Mensinga was born in 1808 in Groningen, Groningen, Nederland; was christened on 22 January 1808 in Groningen, Groningen, Nederland; died in Date unknown.
5. Harmannus Mensinga was born approximately 1815 in Harkstede, Slochteren, Groningen, Nederland; died on 03 April 1828 in Groningen, Groningen, Nederland.
6. Aaffien Gerrits was born on 21 December 1817 in Groningen, Groningen, Nederland; died on 26 December 1817 in Groningen, Groningen, Nederland.
7. Aaffien Gerrits Mensinga was born on 31 July 1819 in Groningen, Groningen, Nederland; died in Date unknown.

Gerrit + Trientje Jans. Trientje was born about 1751 in Workum, Friesland, Nederland; died on 23 March 1820 in Workum, Friesland, Nederland. [Group Sheet] [Family Chart]