For what its worth, there were several Robersons and Rogers in the early history of Richmond Co. which is near Union Co. The Robersons came out of old Rockingham and Orange Co's to the old Anson Co. which included present day Richmond, Montgomery, Stanly and Anson Co's. Don't know the origins of the Rogers line there. If you don't find your answer in Union try Richmond, or Anson if earlier than 1791.