When Maren Kirstine Andersen was born on 7 March 1899, in Ørby, Tranebjerg, Samsø, Holbæk, Denmark, her father, Søren Andersen, was 28 and her mother, Marie Laurine Kirstine Petersen, was 26. She married Morten Willumsen on 17 August 1919, in Ørby, Tranebjerg, Samsø, Holbæk, Denmark. They were the parents of at least 1 son. She lived in Tranebjerg, Holbæk, Denmark in 1930. She died on 3 October 1950, in Tranebjerg, Samsø, Holbæk, Denmark, at the age of 51.