Sveinn Þorsteinsson was born on April 14, 1815 in N. Múlasýsla. He died of smallpox on Mikley in the fall of 1876.
Spouse: 1) Ingibjörg Pálsdóttir d. 1837 2) Guðrún Jónsdóttir b. 1795, d. December 11, 1868 3) Sigurbjörg Björnsdóttir b. August 22, 1827, d. 1895 in Mountain.
Children: With Ingibjörg: 1. Páll b. February 19, 1836, d. same year 2. Una b. March 31, 1837, d. April 1837. No children with Guðrún. With Sigurbjörg: 1. Pálína b. July 22, 1851 2. Katrín Elísabet b. October 21, 1871. Sveinn had children with Anna Hallsdóttir, the widow of Jón Jónsson at Hallbjarnarstaðir: 1. Þorsteinn b. November 19, 1860 2. Kristín b. July 29, 1863 3. Stefanía b. January 9, 1865. Sigurbjörg had 1. Jóhann(es) Vigfússon with Vigfús Guðmundsson 2. Björn Mikaelsson, son of Mikael Gellison 3. Oddur b. July 4, 1868, father unknown.
Sveinn and Sigurbjörg came west with their children and step-children in 1876 and settled in Mikley the same year, naming their land Borðeyri. Sigurbjörg lived a number of years with her children in the Fljóts Settlement, but then moved to N. Dakota in 1880.