seeking info Johnston

Seeking info on Humphrey Johnston (or Johnson) born 1777 approx or possibly 1786. Was a weaver and shown on 1796 flaxgrowers list for Monaghan. Married 1806 to Margaret Whitcraft (or Whitcroft). She was born likely May 1786. They emigrated to Canada via USA around 1810 to 1818 timeframe most likely. I am descendant of Humphrey and Margaret. I have details of the family from 1819 onwards but nothing of them earlier and unfamiliar with Humphrey's ancestors.   All info to Fredrick Johnson in Canada email johnsonfb@tbaytel.net