Þorlákur Pétursson was born in 1842 in Tungusveit in Skagafjarðarsýsla.
Maki: 1) 1864 Sigríður Gottskálksdóttir b. 1823 in Skagafjordur. She died in 1898. 2) Þorbjörg Skúladóttir b. 1852 in Eyjafjarðarsýsla.
Children: Þorlákur had a son, Valdimar, with Maria Bjornsdottir the younger, who was fostered by his brother Jóhannes. The child went west with Jóhannes and grew up there. Sigríður had a daughter, Jórunn Guðmundsdóttir b. 1860, with her first husband. Þorbjörg was a widow with four children when they came west from Akureyri in 1900. The children were 1. Sigurður b. 1881 2. Helga Skúlína b. 1883 3. Jón b. 1885 4. Ragnheiður b. 1890.
Þorlákur and Sigríður emigrated to Canada in 1873. The settled in the Lincoln County Settlement in Minnesota.