When Steinunn Nikulásdóttir was born in 1764, in Háfur, Rangárvallasýsla, Suðurland, Iceland, her father, Nikulás Thorgilsson, was 38 and her mother, Valgerður Þorvaldsdóttir, was 33. She married Ólafur Magnússon on 11 November 1789. They were the parents of at least 6 sons and 3 daughters. She died on 22 August 1825, in Borgarnes, Mýrasýsla, Western Region, Iceland, at the age of 61.