Tonnes was born on Tjørn farm, Bjerkreim, Rogaland County, Norway, and lived there his entire life. He married Kari Ivarsdatter Vasboe in abt. 1869.
He was the third son named Tonnes—two brothers of the same name died before his birth—Tonnes (1837-1837) and Tonnes (1839-1839).
Tonnes Helgesen Tjorn (1841-1916) is 3rd great-grandfather of MKS in the Watne branch.
 Ancestry.com member BASturm (photograph).