Þorsteinn Sigurðsson was born in Skagafjarðarsýsla in 1860.
Spouse: Ingibjörg Guðmundsdóttir born in Skagafjarðarsýsla in 1859.
Children: 1. Hrólfur b. 1885 2. Guðjón b. 1891 3. Björn b. 1895.
Þorsteinn must have emigrated west at the beginning of the 20th century with Hrólf and settled in the Geysir Settlement. Magnús Sigurðsson writes about the settlers in the Geysir Settlement in the Almanak 1932 and says Ingibjörg was sent west a few years later. Margrét Jónsdóttir became a widow at Þingeyrum (1910) following the death of her husband, Guðmundur Guðmundsson. She hired Þorsteinn as her farm manager and formed a company with him. With this arrangement, he came to own half of Þingeyrum, but it was difficult to get this approved in the settlement. Hrólfur married Oddný, daughter of Margrét and Guðmundur. They lived in Selkirk and later moved west to Seattle.