Early genealogies compiled on the Garn family reported that Susan's surname was Pringle. This has been proven to be wrong by Garn family researcher Philip Graham Garn and probably occurred because two of her older sisters married Pringle men and Susan was thought to have lived with one of the families as a child.

Susan's parents were John Martin Cable, AKA Martin John Cable, and Mary Christina Ripley. A power of attorney document, found in the records of Montgomery County, Ohio, establishes that Susan, the wife of John Garn, was the daughter of Martin Cable.

No grave has been found and documented for Susan. Prior to her husband's death, several of their children had already moved to Sandusky County, Ohio. Shortly after his death most of their children were living there and family records show that Susan went to Ohio with the rest of the family after her husband died. She undoubtedly lived with one or another of the children and may have been buried in a family plot on land owned by one of the children. However, around six years before her death, a son-in-law, David Klotz or Klutz, was buried in Metzgar Cemetery (1882 History of Sandusky County History, p. 746). And a grandson, Josiah Garn, was buried there in 1835 according to transcripts of grave marker inscriptions at Metzgar Cemetery that were recorded in 1976 and may be found at the Rutherford B. Hayes Presidential Library in Fremont, Ohio. Therefore, it seems most likely that Susan would have been buried in the same cemetery as family members and that her grave is one of those unmarked graves in the cemetery or perhaps even one with a grave marker that has an illegible inscription.

Birth and death dates given above come from traditions passed to descendants.