When Katrín Jónsdóttir was born in 1725, in Skogar Undir Eyjafjollum, Rangárvallasýsla, Suðurland, Iceland, her father, Jon Jonsson, was 25 and her mother, Olof Egilsson, was 22. She married Olafur Jonsson about 1749, in Iceland. They were the parents of at least 3 daughters. She died on 19 January 1805, in Rangárvallasýsla, Suðurland, Iceland, at the age of 80, and was buried in Skogar, Rangárvallasýsla, Suðurland, Iceland.