I, too, have a Sherritt great, great grandmother.She was Rebecca SHERRITT (born in Ireland about 1806) who came to Argenteuil Co., Quebec. She had at least one brother, George, although I believe there were others but I haven't proved the links yet.
She married Andrew TIMMINS in 1829.They had a large family before moving to Dundas Co., Ontario in the early 1850s.
Several Sherritts came to Huron Co., Ontario.Some direct from Ireland and others via Quebec.Many of these settled on Canada Company lands.
I am collecting information on Irish SHERRITT families in Quebec and Ontario and am interested in communicating with others researching these lines.Glad to share whatever I have.