Johannes married Maria Anna Gast on 19 May 1799 in Wissembourg, Bas-Rhin, Alsace, France. Maria (daughter of Johannes Kaspar Gast and Anna Maria Naab) was born on 19 Jun 1775 in Steinfeld, Pfalz; was christened on 19 Jun 1775 in Steinfeld, Pfalz. [Group Sheet] [Family Chart]

1. Franz Peter Lau was born on 5 Jul 1802 in Steinfeld, Pfalz, Bayern; was christened on 5 Jul 1802 in Steinfeld, Pfalz, Bayern.
2. Cornelius Lau was born on 29 Jul 1804 in Steinfeld, Pfalz, Bayern; was christened on 29 Jul 1804 in Steinfeld, Pfalz, Bayern.
3. Martin Lau was born on 16 Jan 1810 in Steinfeld, Pfalz, Bayern; was christened on 16 Jan 1810 in Steinfeld, Pfalz, Bayern.
4. Bonifacius Lau was born on 19 Aug 1812 in Steinfeld, Pfalz, Bayern; was christened on 19 Aug 1812 in Steinfeld, Pfalz, Bayern.
5. Johannes Adam Lau was born on 7 Apr 1815 in Steinfeld, Pfalz, Bayern; was christened on 7 Apr 1815 in Steinfeld, Pfalz, Bayern.
6. Ludwig Lau was born in 1821 in Steinfeld, Pfalz, Bayern.