Wife of Child #1 Katharina Barbara Riel, age 20, from Stephan
Child #2 Johann Georg Wittmann, age 2
Child #3 Margaretha Louisa Wittmann, age 18
Child #4 Katharina Elisabeth Wittmann, age 14
Child #5 Sophia Barbara Wittmann, age 9
Child #6 Juliana Wittmann, age 7
Child #7 Anna Margaretha Wittmann, age 4
She appears to be his second wife. His first wife in the 1775 census is the same age as he is; her name is Margaretha Barbara. His second wife is three years younger than he is, named Anna Barbara.
↑The 1775 and 1798 Census of the German Colony on the Volga, Lesnoy Karamysh, also known as Grimm; Published by the American Historical Society of Germans from Russia, Lincoln, Nebraska, USA; Published date: 1995; family #8 in the 1798 census, Martin Wittmann family.