Klug was born as Petra Anderson on a farm near Rhame, North Dakota on 4 July 1914. She was the second of four daughters born to Norwegian immigrants Alex and Minnie (née Pederson) Anderson, who married on 1 January 1911. Her three sisters were Agnes, Eleanor, and Hazel. Her father and uncle homesteaded in the early 1900s, journeying to Griffin, North Dakota by train.
As a child, Klug attended Langberg School. She recalled that her mother would do all the housework for them and her parents, and hand-made all her daughters’ clothes. Klug wore her prom dress that her mother had made with pride. She grew up playing with homemade ragdolls, and remembers a teddy bear from her childhood; there were several years when the family did not have a Christmas tree.
In the late 1920s, Klug’s family became the first in the area to own a telephone. She and her sisters would assist their father with farm work, particularly tending the horses, cows, and hay bales. The family mainly spoke Norwegian at home, though Klug and her sisters learnt English once they started school.
Klug graduated high school in Rhame as valedictorian, then attended Aberdeen Business School for seven months. Throughout the 1930s, she worked at a land office and Farmers’ Union. She married Bruno Klug in 1941 and had three children: Bonnie, Dale, and Linda. She sold eggs and cream to support the family. In 1952, the Klugs built a new house.
Throughout her adult life, there were many groups and organisations that Klug was a part of. She drove until the age of 100, and made five trips to Norway for family reunions. At the age of 104, she moved from her farm into a nursing home in Bowman, North Dakota, where she still lives today as a supercentenarian.
Following the death of 113-year-old Clarabell Demers on 17 January 2024, Klug became North Dakota’s oldest known resident.
Klug’s age was verified by Fabrizio Villatoro and validated by LongeviQuest on 18 July 2024.