Marcus married Magdalena Leininger before 1910 in Boone County, Iowa, USA. Magdalena (daughter of Joseph Leininger and Margaretha Bereswill) was born on 1 Jul 1879 in Hooppole, Henry County, Illinois, USA; died on 9 Sep 1936 in Boone County, Iowa, USA; was buried in Sacred Heart Cemetery, Boone, Boone County, Iowa, USA. [Group Sheet] [Family Chart]

1. Agatha J. Wilhelm
2. Clarence Albert Wilhelm was born on 21 Sep 1915 in Boone County, Iowa, USA; died in 0Dec 1987 in Ogden, Boone County, Iowa, USA.
3. Leonard H. Wilhelm