Stewart Genealogy

I am a descendant of John Stewart (died 1891) and his wife Ann Thornhill (died 1893), both born around 1805 in Northern Ireland. They emigrated to Fenelon Falls, Ontario, Canada around 1840. They had eight children, William (moved to Manitoba), James, Henry (moved to Michigan), Maggie (married George Strong), Mary (married a "Polsom"), John (moved to Michigan), Joseph (moved to Michigan), and Robert (lived on family farm). I am interest in contacting other descendants and searching for the family history in Northern Ireland.