Does anyone know the lineage of James, Jesse, William, or Barnett Dempsey of Spartanburg County, SC? They appear in multiple censuses from 1800 on.

My g-g-g-g-grandfather, Nathan Dempsey, was supposed to have been born in Spartanburg County in 1815 before moving up to Carter County, TN. But I have no name for his father. Maybe someone descended from one of the aforementioned Dempseys could shed some light on this mystery.