Hello Lynne, I suspect that John is a grandson of Robert FERGUSSON who wasborn in Moniave, near Dumfries, in Scotland, around 1745. He married Elizabeth BALLANTINE in 1788. Robert "owned Nanjemoy, an estate in Charles County, though he lived in Georgetown and later at 'Mulberry Grove,' also in Charles County, near Port Tobacco." http://www.lib.umd.edu/archivesum/rguide/histpre.jsphttp://www.lib.umd.edu/archivesum/rguide/histpre.jsp
Have made any progress since your initial post?
Elizabeth appears to be a widow for in the 24 Oct 1850 Census, Hill Top, Charles County the family is listed as: Elizabeth Ferguson, 36, MD Robert, 8, MD Wm, 6, MD